Every CVE Search/ Get API key

CVE-2026-55671

ZITADEL: Server-Side Request Forgery (SSRF) and Denylist Bypass in Outgoing HTTP Components

2.3 LowFix available

ZITADEL is an open source identity management platform. From 4.0.0-rc.1 through 4.15.1, ZITADEL's HTTP notification channels, OIDC BackChannel Logout, and SAML metadata URL fetches do not consistently validate user-defined URLs against protected denylist handling, allowing server-side requests to loopback, internal IP, link-local, or redirected endpoints through DNS rebinding, redirects, or protocol downgrades. This issue is fixed in version 4.15.2.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
Low
Availability
None

Exploit likelihood

0.41%Up 0.2 points since Jul 11, 2026
90%50%10%1%

What each source reports

CVE List Score used 2.3

ZITADEL: Server-Side Request Forgery (SSRF) and Denylist Bypass in Outgoing HTTP Components

ZITADEL is an open source identity management platform. From 4.0.0-rc.1 through 4.15.1, ZITADEL's HTTP notification channels, OIDC BackChannel Logout, and SAML metadata URL fetches do not consistently validate user-defined URLs against protected denylist handling, allowing server-side requests to loopback, internal IP, link-local, or redirected endpoints through DNS rebinding, redirects, or protocol downgrades. This issue is fixed in version 4.15.2.

Record
CVE-2026-55671
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-918
Updated
2026-11-02
EUVDEUVD-2026-42978 2.3

ZITADEL is an open source identity management platform. From 4.0.0-rc.1 through 4.15.1, ZITADEL's HTTP notification channels, OIDC BackChannel Logout, and SAML metadata URL fetches do not consistently validate user-defined URLs against protected denylist handling, allowing server-side requests to loopback, internal IP, link-local, or redirected endpoints through DNS rebinding, redirects, or protocol downgrades. This issue is fixed in version 4.15.2.

Record
EUVD-2026-42978
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-29jh-8cfq-rr8x 2.3

ZITADEL: Server-Side Request Forgery (SSRF) and Denylist Bypass in Outgoing HTTP Components

Summary

A Server-Side Request Forgery (SSRF) vulnerability was discovered in Zitadel affecting:

  • HTTP Notification Channels: Used as an alternative to SMTP/Twilio configurations, sending payloads to user-defined URLs via HTTP POST webhooks.
  • OIDC BackChannel Logout: Terminates sessions across different applications. When a session ends, the Zitadel server sends an HTTP POST request to configured endpoints.
  • SAML Metadata URL Fetches: Fetches SAML metadata configurations from user-provided external URLs.

User-defined URLs in these components were not properly validated against an internal denylist, allowing potentially malicious URLs to bypass restrictions. Furthermore, the existing denylist mechanism previously introduced for Actions was found to be vulnerable to DNS rebinding, HTTP redirects, and protocol downgrades (HTTPS to HTTP), and it missed several common local network default entries.

Because an attacker can supply arbitrary URLs—including loopback addresses, internal IPs, or cloud link-local addresses—they could potentially gather internal network architecture details, scan internal ports, or interact with unauthorized internal services and infrastructure.

Impact

When a user-supplied URL points to a local host or internal IP address, an adversary can perform a Server-Side Request Forgery (SSRF) attack. This allows them to map internal network structures and exploit exposed internal services.

By leveraging DNS rebinding, an attacker could also bypass standard DNS-level checks, creating Time-of-Check to Time-of-Use (TOCTOU) gaps to access restricted internal endpoints. Additionally, vulnerabilities to HTTP redirects and protocol downgrades could allow attackers to manipulate the request flow or intercept sensitive communication.

Notably, if Zitadel is deployed within cloud environments (such as AWS, GCP, or Azure) that still permit legacy IMDSv1 or unauthenticated cloud metadata endpoints (169.254.169.254), an attacker could theoretically attempt to target these metadata services.

While Zitadel expects specific schemas or response formats for these features (which inherently limits data exfiltration capabilities and reduces the severe execution of the threat vector), users are strongly advised to patch immediately.

Affected Versions

Systems running one of the following versions are affected:

  • 4.x: 4.0.0 through 4.15.1 (including RC versions)
  • 3.x: 3.0.0 through 3.4.11 (including RC versions)

Patches

The vulnerability has been addressed in the latest releases. The patch resolves the issue by securely validating target URLs against a hardened denylist. By default, localhost, loopback IPs, and standard internal network blocks are denied.

Note on Backports: This fix was only released on v4.x. While some of the affected components were generally available (GA), backporting the security fix to v3.x was not feasible due to the extensive code refactoring required to implement the unified network client securely. Please check the workarounds section if an upgrade to v4.x is not immediately possible.

  • 4.x: Upgrade to $\ge$4.15.2
  • 3.x: Update to $\ge$v4.15.2 or check out workarounds

Workarounds

The recommended solution is to update Zitadel to a patched version.

If an immediate upgrade is not possible, you can mitigate the risk by implementing strict network policies, egress firewalls, or reverse proxy rules within your infrastructure to block Zitadel from initiating outbound connections to your internal network, loopback interfaces, or cloud metadata endpoints. Note that managing these network controls is outside the scope of Zitadel's native configurations.

Questions

If you have any questions or comments about this advisory, please email us at [email protected]

###…

Record
GHSA-29jh-8cfq-rr8x
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-918
Updated
2026-11-02
NVD 2.3

ZITADEL is an open source identity management platform. From 4.0.0-rc.1 through 4.15.1, ZITADEL's HTTP notification channels, OIDC BackChannel Logout, and SAML metadata URL fetches do not consistently validate user-defined URLs against protected denylist handling, allowing server-side requests to loopback, internal IP, link-local, or redirected endpoints through DNS rebinding, redirects, or protocol downgrades. This issue is fixed in version 4.15.2.

Record
CVE-2026-55671
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/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
Weakness
CWE-918
Updated
2026-11-02
OSV 2.3

ZITADEL: Server-Side Request Forgery (SSRF) and Denylist Bypass in Outgoing HTTP Components

ZITADEL is an open source identity management platform. From 4.0.0-rc.1 through 4.15.1, ZITADEL's HTTP notification channels, OIDC BackChannel Logout, and SAML metadata URL fetches do not consistently validate user-defined URLs against protected denylist handling, allowing server-side requests to loopback, internal IP, link-local, or redirected endpoints through DNS rebinding, redirects, or protocol downgrades. This issue is fixed in version 4.15.2.

Record
CVE-2026-55671
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-918
Updated
2026-11-02
OSVGHSA-29jh-8cfq-rr8x 2.3

ZITADEL: Server-Side Request Forgery (SSRF) and Denylist Bypass in Outgoing HTTP Components

Summary

A Server-Side Request Forgery (SSRF) vulnerability was discovered in Zitadel affecting:

  • HTTP Notification Channels: Used as an alternative to SMTP/Twilio configurations, sending payloads to user-defined URLs via HTTP POST webhooks.
  • OIDC BackChannel Logout: Terminates sessions across different applications. When a session ends, the Zitadel server sends an HTTP POST request to configured endpoints.
  • SAML Metadata URL Fetches: Fetches SAML metadata configurations from user-provided external URLs.

User-defined URLs in these components were not properly validated against an internal denylist, allowing potentially malicious URLs to bypass restrictions. Furthermore, the existing denylist mechanism previously introduced for Actions was found to be vulnerable to DNS rebinding, HTTP redirects, and protocol downgrades (HTTPS to HTTP), and it missed several common local network default entries.

Because an attacker can supply arbitrary URLs—including loopback addresses, internal IPs, or cloud link-local addresses—they could potentially gather internal network architecture details, scan internal ports, or interact with unauthorized internal services and infrastructure.

Impact

When a user-supplied URL points to a local host or internal IP address, an adversary can perform a Server-Side Request Forgery (SSRF) attack. This allows them to map internal network structures and exploit exposed internal services.

By leveraging DNS rebinding, an attacker could also bypass standard DNS-level checks, creating Time-of-Check to Time-of-Use (TOCTOU) gaps to access restricted internal endpoints. Additionally, vulnerabilities to HTTP redirects and protocol downgrades could allow attackers to manipulate the request flow or intercept sensitive communication.

Notably, if Zitadel is deployed within cloud environments (such as AWS, GCP, or Azure) that still permit legacy IMDSv1 or unauthenticated cloud metadata endpoints (169.254.169.254), an attacker could theoretically attempt to target these metadata services.

While Zitadel expects specific schemas or response formats for these features (which inherently limits data exfiltration capabilities and reduces the severe execution of the threat vector), users are strongly advised to patch immediately.

Affected Versions

Systems running one of the following versions are affected:

  • 4.x: 4.0.0 through 4.15.1 (including RC versions)
  • 3.x: 3.0.0 through 3.4.11 (including RC versions)

Patches

The vulnerability has been addressed in the latest releases. The patch resolves the issue by securely validating target URLs against a hardened denylist. By default, localhost, loopback IPs, and standard internal network blocks are denied.

Note on Backports: This fix was only released on v4.x. While some of the affected components were generally available (GA), backporting the security fix to v3.x was not feasible due to the extensive code refactoring required to implement the unified network client securely. Please check the workarounds section if an upgrade to v4.x is not immediately possible.

  • 4.x: Upgrade to $\ge$4.15.2
  • 3.x: Update to $\ge$v4.15.2 or check out workarounds

Workarounds

The recommended solution is to update Zitadel to a patched version.

If an immediate upgrade is not possible, you can mitigate the risk by implementing strict network policies, egress firewalls, or reverse proxy rules within your infrastructure to block Zitadel from initiating outbound connections to your internal network, loopback interfaces, or cloud metadata endpoints. Note that managing these network controls is outside the scope of Zitadel's native configurations.

Questions

If you have any questions or comments about this advisory, please email us at [email protected]

###…

Record
GHSA-29jh-8cfq-rr8x
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-918
Updated
2026-11-02
OSVGO-2026-5059 No score

ZITADEL: Server-Side Request Forgery (SSRF) and Denylist Bypass in Outgoing HTTP Components in github.com/zitadel/zitadel

ZITADEL: Server-Side Request Forgery (SSRF) and Denylist Bypass in Outgoing HTTP Components in github.com/zitadel/zitadel

Record
GO-2026-5059
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

Affected products

Affected packages

Affected packages
PackageAffectedFixed
github.com/zitadel/zitadel
Go
 before 1.80.0-v2.20.0.20260615133614-8e82ec1cb9a2
1.80.0-v2.20.0.20260615133614-8e82ec1cb9a2
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
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

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

In short

CVE-2026-55671 is a low vulnerability (CVSS 2.3) in Zitadel, published June 18, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.41%, the 35th percentile. Fixed in github.com/zitadel/zitadel 1.80.0-v2.20.0.20260615133614-8e82ec1cb9a2.

References

Show 194 moreShow less
This page doesn't list everything

Left out here: 1,542 references and the rest of 3 source descriptions. The JSON record has them.

Pages All vulnerabilities Browse Docs Sources Guide Get API key
MoveEnter Open