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CVE-2026-27586

Caddy's mTLS client authentication silently fails open when CA certificate file is missing or malformed

8.8 HighFix available

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, two swallowed errors in ClientAuthentication.provision() cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary. Any deployment using trusted_ca_cert_file or trusted_ca_certs_pem_files for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured. Version 2.11.1 fixes the vulnerability.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
None

Exploit likelihood

0.29%Up 0.2 points since Feb 25, 2026
90%50%10%1%

What each source reports

CVE List Score used 8.8

Caddy's mTLS client authentication silently fails open when CA certificate file is missing or malformed

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, two swallowed errors in ClientAuthentication.provision() cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary. Any deployment using trusted_ca_cert_file or trusted_ca_certs_pem_files for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured. Version 2.11.1 fixes the vulnerability.

Record
CVE-2026-27586
CVSS 4.0
8.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
Weakness
CWE-755
Updated
2026-11-02
EUVDEUVD-2026-8541 8.8

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, two swallowed errors in ClientAuthentication.provision() cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary. Any deployment using trusted_ca_cert_file or trusted_ca_certs_pem_files for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured. Version 2.11.1 fixes the vulnerability.

Record
EUVD-2026-8541
CVSS 4.0
8.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
Updated
2026-11-02
GitHub AdvisoriesGHSA-hffm-g8v7-wrv7 8.8

Caddy: mTLS client authentication silently fails open when CA certificate file is missing or malformed

Summary

Two swallowed errors in ClientAuthentication.provision() cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary.

Details

In modules/caddytls/connpolicy.go, the provision() method has two return nil statements that should be return err:

Bug #1 — line 787:

ders, err := convertPEMFilesToDER(fpath)
if err != nil {
    return nil  // BUG: should be "return err"
}

Bug #2 — line 800:

err := caPool.Provision(ctx)
if err != nil {
    return nil  // BUG: should be "return err"
}

Compare with line 811 which correctly returns the error:

caRaw, err := ctx.LoadModule(clientauth, "CARaw")
if err != nil {
    return err  // CORRECT
}

When the error is swallowed on line 787, the chain is:

  1. TrustedCACerts remains empty (no DER data appended from the file)
  2. The len(clientauth.TrustedCACerts) > 0 guard on line 794 is false — skipped
  3. clientauth.CARaw is nil — line 806 returns nil
  4. clientauth.ca remains nil — no CA pool was created
  5. provision() returns nil — caller thinks provisioning succeeded

Then in ConfigureTLSConfig():

  1. Active() returns true because TrustedCACertPEMFiles is non-empty
  2. Default mode is set to RequireAndVerifyClientCert (line 860)
  3. But clientauth.ca is nil, so cfg.ClientCAs is never set (line 867 skipped)
  4. Go's crypto/tls with RequireAndVerifyClientCert + nil ClientCAs verifies client certs against the system root pool instead of the intended CA

The fix is changing return nil to return err on lines 787 and 800.

PoC

  1. Configure Caddy with mTLS pointing to a nonexistent CA file:
{
    "apps": {
        "http": {
            "servers": {
                "srv0": {
                    "listen": [":443"],
                    "tls_connection_policies": [{
                        "client_authentication": {
                            "trusted_ca_certs_pem_files": ["/nonexistent/ca.pem"]
                        }
                    }]
                }
            }
        }
    }
}

  1. Start Caddy — it starts without any error or warning.

  2. Connect with any client certificate (even self-signed):

openssl s_client -connect localhost:443 -cert client.pem -key client-key.pem
  1. The TLS handshake succeeds despite the certificate not being signed by the intended CA.

A full Go test that proves the bug end-to-end (including a successful TLS handshake with a random self-signed client cert) is here: https://gist.github.com/moscowchill/9566c79c76c0b64c57f8bd0716f97c48

Test output:

=== RUN   TestSwallowedErrorMTLSFailOpen
    BUG CONFIRMED: provision() swallowed the error from a nonexistent CA file.
    tls.Config has RequireAndVerifyClientCert but ClientCAs is nil.
    CRITICAL: TLS handshake succeeded with a self-signed client cert!
    The server accepted a client certificate NOT signed by the intended CA.
--- PASS: TestSwallowedErrorMTLSFailOpen (0.03s)

Impact

Any deployment using trusted_ca_cert_file or trusted_ca_certs_pem_files for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured.

Record
GHSA-hffm-g8v7-wrv7
CVSS 4.0
8.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
Weakness
CWE-755
Updated
2026-11-02
NVD 8.8

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, two swallowed errors in ClientAuthentication.provision() cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary. Any deployment using trusted_ca_cert_file or trusted_ca_certs_pem_files for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured. Version 2.11.1 fixes the vulnerability.

Record
CVE-2026-27586
CVSS 4.0
8.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness
CWE-755
Updated
2026-11-02
OSVALPINE-CVE-2026-27586 9.1

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, two swallowed errors in ClientAuthentication.provision() cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary. Any deployment using trusted_ca_cert_file or trusted_ca_certs_pem_files for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured. Version 2.11.1 fixes the vulnerability.

Record
ALPINE-CVE-2026-27586
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Updated
2026-11-03
OSV 8.8

Caddy's mTLS client authentication silently fails open when CA certificate file is missing or malformed

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, two swallowed errors in ClientAuthentication.provision() cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary. Any deployment using trusted_ca_cert_file or trusted_ca_certs_pem_files for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured. Version 2.11.1 fixes the vulnerability.

Record
CVE-2026-27586
CVSS 4.0
8.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
Weakness
CWE-755
Updated
2026-11-02
Show 6 moreShow less
OSVDEBIAN-CVE-2026-27586 9.1

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, two swallowed errors in ClientAuthentication.provision() cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary. Any deployment using trusted_ca_cert_file or trusted_ca_certs_pem_files for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured. Version 2.11.1 fixes the vulnerability.

Record
DEBIAN-CVE-2026-27586
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVGHSA-hffm-g8v7-wrv7 8.8

Caddy: mTLS client authentication silently fails open when CA certificate file is missing or malformed

Summary

Two swallowed errors in ClientAuthentication.provision() cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary.

Details

In modules/caddytls/connpolicy.go, the provision() method has two return nil statements that should be return err:

Bug #1 — line 787:

ders, err := convertPEMFilesToDER(fpath)
if err != nil {
    return nil  // BUG: should be "return err"
}

Bug #2 — line 800:

err := caPool.Provision(ctx)
if err != nil {
    return nil  // BUG: should be "return err"
}

Compare with line 811 which correctly returns the error:

caRaw, err := ctx.LoadModule(clientauth, "CARaw")
if err != nil {
    return err  // CORRECT
}

When the error is swallowed on line 787, the chain is:

  1. TrustedCACerts remains empty (no DER data appended from the file)
  2. The len(clientauth.TrustedCACerts) > 0 guard on line 794 is false — skipped
  3. clientauth.CARaw is nil — line 806 returns nil
  4. clientauth.ca remains nil — no CA pool was created
  5. provision() returns nil — caller thinks provisioning succeeded

Then in ConfigureTLSConfig():

  1. Active() returns true because TrustedCACertPEMFiles is non-empty
  2. Default mode is set to RequireAndVerifyClientCert (line 860)
  3. But clientauth.ca is nil, so cfg.ClientCAs is never set (line 867 skipped)
  4. Go's crypto/tls with RequireAndVerifyClientCert + nil ClientCAs verifies client certs against the system root pool instead of the intended CA

The fix is changing return nil to return err on lines 787 and 800.

PoC

  1. Configure Caddy with mTLS pointing to a nonexistent CA file:
{
    "apps": {
        "http": {
            "servers": {
                "srv0": {
                    "listen": [":443"],
                    "tls_connection_policies": [{
                        "client_authentication": {
                            "trusted_ca_certs_pem_files": ["/nonexistent/ca.pem"]
                        }
                    }]
                }
            }
        }
    }
}

  1. Start Caddy — it starts without any error or warning.

  2. Connect with any client certificate (even self-signed):

openssl s_client -connect localhost:443 -cert client.pem -key client-key.pem
  1. The TLS handshake succeeds despite the certificate not being signed by the intended CA.

A full Go test that proves the bug end-to-end (including a successful TLS handshake with a random self-signed client cert) is here: https://gist.github.com/moscowchill/9566c79c76c0b64c57f8bd0716f97c48

Test output:

=== RUN   TestSwallowedErrorMTLSFailOpen
    BUG CONFIRMED: provision() swallowed the error from a nonexistent CA file.
    tls.Config has RequireAndVerifyClientCert but ClientCAs is nil.
    CRITICAL: TLS handshake succeeded with a self-signed client cert!
    The server accepted a client certificate NOT signed by the intended CA.
--- PASS: TestSwallowedErrorMTLSFailOpen (0.03s)

Impact

Any deployment using trusted_ca_cert_file or trusted_ca_certs_pem_files for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured.

Record
GHSA-hffm-g8v7-wrv7
CVSS 4.0
8.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
Weakness
CWE-755
Updated
2026-11-02
OSVUBUNTU-CVE-2026-27586 8.8

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, two swallowed errors in ClientAuthentication.provision() cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary. Any deployment using trusted_ca_cert_file or trusted_ca_certs_pem_files for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured. Version 2.11.1 fixes the vulnerability.

Record
UBUNTU-CVE-2026-27586
CVSS 4.0
8.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVGO-2026-4539 No score

Caddy mTLS authentication fails open in github.com/caddyserver/caddy/v2

Caddy mTLS authentication fails open in github.com/caddyserver/caddy/v2

Record
GO-2026-4539
Updated
2026-11-02
OSVopenSUSE-SU-2026:21483-1 No score

Security update for govulncheck-vulndb

This update for govulncheck-vulndb fixes the following issues:

  • Update to version 0.0.20260723T184607 2026-07-23T18:46:07Z (jsc#PED-11136).

Go CVE Numbering Authority IDs added or updated with aliases:

  • GO-2026-4730 CVE-2026-33022 GHSA-cv4x-93xx-wgfj
  • GO-2026-4761 CVE-2026-33211 GHSA-j5q5-j9gm-2w5c
  • GO-2026-5102 CVE-2026-45021 GHSA-3vcp-chfh-f6r2
  • GO-2026-5272 CVE-2026-40938 GHSA-94jr-7pqp-xhcq
  • GO-2026-5486 CVE-2026-40924 GHSA-m2cx-gpqf-qf74
  • GO-2026-5542 CVE-2026-40090 GHSA-pj97-4p9w-gx3q
  • GO-2026-5630 CVE-2026-25542 GHSA-rmx9-2pp3-xhcr
  • GO-2026-5643 CVE-2026-40923 GHSA-rx35-6rhx-7858
  • GO-2026-5675 CVE-2026-41492 GHSA-vvf7-6rmr-m29q
  • GO-2026-5711 CVE-2026-40161 GHSA-wjxp-xrpv-xpff
  • GO-2026-5746 CVE-2026-41567 GHSA-x86f-5xw2-fm2r
  • GO-2026-5749 CVE-2026-41328 GHSA-x92x-px7w-4gx4
  • GO-2026-5837 CVE-2026-44840 GHSA-q2m9-6jp9-c6mc
  • GO-2026-5929 CVE-2026-44342 GHSA-26v7-h57m-gh9m
  • GO-2026-5930 CVE-2026-33655 GHSA-6qcr-qxgr-m7fv
  • GO-2026-5933 GHSA-3g4q-2f67-2gvh
  • GO-2026-5934 GHSA-59qp-cfj3-rp64
  • GO-2026-5935 GHSA-7856-g3gv-9wq8
  • GO-2026-5936 CVE-2026-53552 GHSA-26rh-24rg-j3vv
  • GO-2026-5937 CVE-2026-53508 GHSA-2jcc-mxv7-p3f9
  • GO-2026-5938 CVE-2026-53553 GHSA-4g5x-hcwm-82jw
  • GO-2026-5939 CVE-2026-10517 GHSA-698x-9w2p-7vvp
  • GO-2026-5940 CVE-2026-53572 GHSA-6w3m-4hhp-775q
  • GO-2026-5941 CVE-2026-53487 GHSA-gvhc-wv3v-7pf8
  • GO-2026-5942 CVE-2026-46600
  • GO-2026-5944 CVE-2026-50197 GHSA-659f-rgp5-w4wf
  • GO-2026-5945 CVE-2026-6815 GHSA-rmxx-v9rj-vpvg
  • GO-2026-5946 CVE-2026-52831 GHSA-v5px-423j-pf7p
  • GO-2026-5947 CVE-2026-53649 GHSA-xqhv-chqm-fhcc
  • GO-2026-5948 CVE-2026-50554 GHSA-588f-fvcv-xhvf
  • GO-2026-5949 CVE-2026-50553 GHSA-rqrh-8wpv-x7hh
  • GO-2026-5950 CVE-2026-53602 GHSA-339v-266x-79xr
  • GO-2026-5951 CVE-2026-10219 GHSA-6jm8-4fhr-5w64
  • GO-2026-5952 CVE-2026-49834 GHSA-9vcr-p3rj-q5q6
  • GO-2026-5953 CVE-2026-9094 GHSA-c9w5-qp6m-m395
  • GO-2026-5956 CVE-2026-55252 GHSA-h5g6-xmh4-hc37
  • GO-2026-5957 CVE-2026-54158 GHSA-5xfx-xj4h-5p7r
  • GO-2026-5958 CVE-2026-54068 GHSA-gcm7-57gf-953c
  • GO-2026-5959 CVE-2026-54072 GHSA-h29v-hj44-q8cv
  • GO-2026-5961 CVE-2026-54069 GHSA-hvr9-72v2-fff3
  • GO-2026-5962 CVE-2026-54088 GHSA-m93h-4hw7-5qcm
  • GO-2026-5963 CVE-2026-54067 GHSA-mvjr-vv3c-w4qv
  • GO-2026-5964 CVE-2026-54066 GHSA-p4m3-mgmm-c664
  • GO-2026-5965 CVE-2026-54070 GHSA-w7cg-whh7-xp28
  • GO-2026-5966 CVE-2026-54089 GHSA-xqp3-jq6g-x3qm
  • GO-2026-5967 CVE-2026-50551 GHSA-56mp-4f3v-fgj2
  • GO-2026-5968 CVE-2026-54174 GHSA-fpg8-7664-jc5q
  • GO-2026-5969 GHSA-g936-7jqj-mwv8
  • GO-2026-5970 CVE-2026-56852
  • GO-2026-5973 CVE-2026-54250 GHSA-jxr7-mqhw-9p98
  • GO-2026-5974 CVE-2026-44300 GHSA-wmj8-9953-vff5
  • GO-2026-5975 CVE-2026-50018 GHSA-42j2-w334-qxw7
  • GO-2026-5976 CVE-2026-50141 GHSA-g7mm-9vx7-jm7h
  • GO-2026-5977 CVE-2026-50013 GHSA-qrh4-p6v4-mrfg
  • GO-2026-5978 CVE-2026-50125 GHSA-qw5r-ppcg-f8rj
  • GO-2026-5979 CVE-2026-50006 GHSA-xrcf-6jh3-ggvx
  • GO-2026-5980 CVE-2026-50158 GHSA-2c7f-fxww-6w6c
  • GO-2026-5981 GHSA-mqxv-9rm6-w8qc
  • GO-2026-5982 GHSA-pqg7-v6wh-3pfp
  • GO-2026-5984 CVE-2026-53604 GHSA-2p2f-px33-4vv5
  • GO-2026-5985 GHSA-7rx3-5wx3-5v76
  • GO-2026-5986 CVE-2026-61699 GHSA-cm26-5974-52h8
  • GO-2026-5987 CVE-2026-55513 GHSA-g4x6-jcvr-9m3g
  • GO-2026-5988 CVE-2026-54628 GHSA-hwrq-8wxh-q4xv
  • GO-2026-5989 CVE-2026-55512 GHSA-m3cx-mwpg-32jg
  • GO-2026-5990 CVE-2026-54629 GHSA-mf78-3rpf-r784
  • GO-2026-5991 CVE-2026-53603 GHSA-q4vm-pq3q-8wgq
  • GO-2026-5992 CVE-2026-61549 GHSA-qf34-295c-26v8
  • GO-2026-5996 CVE-2026-54450 GHSA-pph6-vfjv-vpjw
  • GO-2026-5997 CVE-2026-54452 GHSA-xgch-x3mx-cm3c
  • GO-2026-5998 CVE-2026-54495 GHSA-398h-7f66-3h4p
  • GO-2026-5999 CVE-2026-10814 GHSA-jh6h-v6mp-h22v
  • GO-2026-6002 CVE-2026-58196 GHSA-pr64-jmmf-jp54
  • GO-2026-6003 CVE-2026-53714 GHSA-22xc-xg2r-9j7v
  • GO-2026-6004 CVE-2026-52833 GHSA-3v79-m2cg-89ww
  • GO-2026-6005 CVE-2026-53715 GHSA-8fv2-88gg-hm7q
  • GO-2026-6006 CVE-2026-53716 GHSA-cxpq-8v7q-cg56 *…
Record
openSUSE-SU-2026:21483-1
Updated
2026-11-02
OSVSUSE-SU-2026:0757-1 No score

Security update for govulncheck-vulndb

This update for govulncheck-vulndb fixes the following issues:

Update to version 0.0.20260226T182644 2026-02-26T18:26:44Z (jsc#PED-11136) Go CVE Numbering Authority IDs added or updated with aliases:

  • GO-2025-4259 CVE-2025-13767 GHSA-fmqf-pmcm-8cx9
  • GO-2025-4260 CVE-2025-64641 GHSA-vww6-79rv-3j4x
  • GO-2026-4282 CVE-2017-18873 GHSA-x6mw-hf2j-vqpc
  • GO-2026-4305 CVE-2017-18903 GHSA-fcwg-45jh-5qhf
  • GO-2026-4325 CVE-2025-14822 GHSA-9r42-rhw3-2222
  • GO-2026-4326 CVE-2025-14435 GHSA-mx8m-v8qm-xwr8
  • GO-2026-4332 CVE-2026-23644 GHSA-2657-3c98-63jq
  • GO-2026-4348 CVE-2026-23991 GHSA-846p-jg2w-w324
  • GO-2026-4349 CVE-2026-23992 GHSA-fphv-w9fq-2525
  • GO-2026-4377 CVE-2026-24686 GHSA-jqc5-w2xx-5vq4
  • GO-2026-4410 CVE-2026-25140 GHSA-f4w5-5xv9-85f6
  • GO-2026-4502 CVE-2026-25766 GHSA-pgvm-wxw2-hrv9
  • GO-2026-4534 CVE-2026-25899 GHSA-2mr3-m5q5-wgp6
  • GO-2026-4535 CVE-2026-27585 GHSA-4xrr-hq4w-6vf4
  • GO-2026-4536 CVE-2026-27590 GHSA-5r3v-vc8m-m96g
  • GO-2026-4537 CVE-2026-27589 GHSA-879p-475x-rqh2
  • GO-2026-4538 CVE-2026-27587 GHSA-g7pc-pc7g-h8jh
  • GO-2026-4539 CVE-2026-27586 GHSA-hffm-g8v7-wrv7
  • GO-2026-4540 CVE-2026-25891 GHSA-m3c2-496v-cw3v
  • GO-2026-4541 CVE-2026-27588 GHSA-x76f-jf84-rqj8
  • GO-2026-4543 CVE-2026-25882 GHSA-mrq8-rjmw-wpq3
  • GO-2026-4559 CVE-2026-27141

Update to version 0.0.20260225T230704 2026-02-25T23:07:04Z.

  • GO-2026-4358 CVE-2026-24137 GHSA-fcv2-xgw5-pqxf
  • GO-2026-4361 GHSA-c32p-wcqj-j677
  • GO-2026-4394 CVE-2026-24051 GHSA-9h8m-3fm2-qjrq
  • GO-2026-4399 CVE-2026-25518 GHSA-gx3x-vq4p-mhhv
  • GO-2026-4507 CVE-2026-26314 GHSA-2gjw-fg97-vg3r
  • GO-2026-4508 CVE-2026-26313 GHSA-689v-6xwf-5jf3
  • GO-2026-4509 CVE-2026-27017 GHSA-7m29-f4hw-g2vx
  • GO-2026-4511 CVE-2026-26315 GHSA-m6j8-rg6r-7mv8
  • GO-2026-4512 CVE-2026-26995 GHSA-rrxv-pmq9-x67r
  • GO-2026-4531 CVE-2026-25591 GHSA-w6x6-9fp7-fqm4
  • GO-2026-4532 CVE-2026-25802 GHSA-299v-8pq9-5gjq
  • GO-2026-4533 CVE-2026-27571 GHSA-qrvq-68c2-7grw
  • GO-2026-4542 CVE-2026-27598 GHSA-6v48-fcq6-ff23
  • GO-2026-4545 CVE-2025-50180 GHSA-3c9r-837r-qqm4
  • GO-2026-4546 CVE-2026-27611 GHSA-8vrh-3pm2-v4v6
  • GO-2026-4547 CVE-2026-27626 GHSA-49gm-hh7w-wfvf
  • GO-2026-4548 GHSA-2phg-qgmm-r638

Update to version 0.0.20260223T182315 2026-02-23T18:23:15Z.

  • GO-2026-4392 CVE-2026-24845 GHSA-9m43-p3cx-w8j5
  • GO-2026-4434 CVE-2023-43635 GHSA-4jvr-vj2c-8q37
  • GO-2026-4435 CVE-2023-43636 GHSA-5h7v-g49c-h887
  • GO-2026-4436 CVE-2023-43637 GHSA-g7vp-j25f-h34p
  • GO-2026-4442 GHSA-x9p2-77v6-6vhf
  • GO-2026-4444 CVE-2026-23989 GHSA-9j2f-3rj3-wgpg
  • GO-2026-4445 CVE-2026-25760 GHSA-2286-hxv5-cmp2
  • GO-2026-4446 CVE-2026-24851 GHSA-jq9f-gm9w-rwm9
  • GO-2026-4447 GHSA-vf5j-r2hw-2hrw
  • GO-2026-4448 CVE-2025-64111 GHSA-gg64-xxr9-qhjp
  • GO-2026-4449 CVE-2025-64175 GHSA-p6x6-9mx6-26wj
  • GO-2026-4450 CVE-2026-23632 GHSA-5qhx-gwfj-6jqr
  • GO-2026-4451 CVE-2026-22592 GHSA-cr88-6mqm-4g57
  • GO-2026-4452 CVE-2026-24135 GHSA-jp7c-wj6q-3qf2
  • GO-2026-4453 CVE-2026-23633 GHSA-mrph-w4hh-gx3g
  • GO-2026-4454 GHSA-26gq-grmh-6xm6
  • GO-2026-4455 CVE-2025-70963 GHSA-9f8m-9547-2gqm
  • GO-2026-4456 CVE-2025-13523 GHSA-ffx7-34p2-vm3w
  • GO-2026-4457 CVE-2025-65852 GHSA-rjv5-9px2-fqw6
  • GO-2026-4458 CVE-2026-25793 GHSA-69x3-g4r3-p962
  • GO-2026-4459 CVE-2017-18907 GHSA-42x9-rr3c-gr59
  • GO-2026-4460 CVE-2017-18918 GHSA-5ghq-28r7-qwfj
  • GO-2026-4461 CVE-2026-25804 GHSA-86x4-wp9f-wrr9
  • GO-2026-4462 CVE-2017-18915 GHSA-hxxj-8phw-74vw
  • GO-2026-4463 CVE-2017-18917 GHSA-jxc4-w54c-qv5r
  • GO-2026-4464 CVE-2017-18911 GHSA-m462-mqw4-2c8m
  • GO-2026-4465 GHSA-vhvq-fv9f-wh4q
  • GO-2026-4466 CVE-2026-25791 GHSA-wxrw-gvg8-fqjp
  • GO-2026-4467 CVE-2017-18916 GHSA-x33g-375j-jhf7
  • GO-2026-4471 CVE-2025-66630 GHSA-68rr-p4fp-j59v
  • GO-2026-4473 CVE-2026-25934 GHSA-37cx-329c-33x3
  • GO-2026-4474 CVE-2026-25890 GHSA-4mh3-h929-w968
  • GO-2026-4475 CVE-2026-25889 GHSA-hxw8-4h9j-hq2r
  • GO-2026-4476 CVE-2017-18908…
Record
SUSE-SU-2026:0757-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
github.com/caddyserver/caddy/v2
Go
 before 2.11.1
2.11.1
caddy
Alpine:v3.23
 before 2.11.2-r0
2.11.2-r0
caddy
Alpine:v3.24
 before 2.11.1-r0
2.11.1-r0
caddy
Debian:14
 before 2.11.2-1, plus listed versions
2.11.2-1~bpo13+12.6.2-122.6.2-132.6.2-14
2.11.2-1
govulncheck-vulndb
openSUSE:Leap 15.6
From an advisory covering 104 CVEs
 before 0.0.20260226T182644-150000.1.149.1
0.0.20260226T182644-150000.1.149.1
caddy
Ubuntu:Pro:24.04:LTS
 All versions, plus listed versions
2.6.2-62.6.2-6ubuntu0.24.04.12.6.2-6ubuntu0.24.04.22.6.2-6ubuntu0.24.04.2+esm12.6.2-6ubuntu0.24.04.32.6.2-6ubuntu0.24.04.3+esm12.6.2-6ubuntu0.24.04.3+esm2
 None known
caddy
Ubuntu:25.10
 All versions, plus listed versions
2.6.2-92.6.2-112.6.2-12
 None known
caddy
Ubuntu:26.10
 All versions, plus listed versions
2.6.2-142.11.4-1
 None known
caddy
Ubuntu:Pro:26.04:LTS
 All versions, plus listed versions
2.6.2-122.6.2-142.6.2-14ubuntu0.26.04.1~esm1
 None known
govulncheck-vulndb
openSUSE:Leap 16.0
From an advisory covering 1734 CVEs
 before 0.0.20260723T184607-160000.1.1
0.0.20260723T184607-160000.1.1

History

History
RecordedChangedSources
affected, facts
affected, aliases, referencesOSV
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-27586 is a high vulnerability (CVSS 8.8) in Caddyserver Caddy, published February 24, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.29%, the 22nd percentile. Fixed in github.com/caddyserver/caddy/v2 2.11.1.

References

Show 194 moreShow less
This page doesn't list everything

Left out here: 1,548 references and the rest of 2 source descriptions. The JSON record has them.

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