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CVE-2026-23829

Mailpit has SMTP Header Injection via Regex Bypass

5.3 MediumPublic exploitFix available

Mailpit is an email testing tool and API for developers. Prior to version 1.28.3, Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate RCPT TO and MAIL FROM addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (\r) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude \r and \n when used inside a character class. Version 1.28.3 fixes this issue.

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
None
Integrity
Low
Availability
None

Exploit likelihood

1.40%Up 1.4 points since Jan 19, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.3

Mailpit has SMTP Header Injection via Regex Bypass

Mailpit is an email testing tool and API for developers. Prior to version 1.28.3, Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate RCPT TO and MAIL FROM addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (\r) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude \r and \n when used inside a character class. Version 1.28.3 fixes this issue.

Record
CVE-2026-23829
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-93, CWE-150
Updated
2026-11-02
EUVDEUVD-2026-3297 5.3

Mailpit is an email testing tool and API for developers. Prior to version 1.28.3, Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate RCPT TO and MAIL FROM addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (\r) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude \r and \n when used inside a character class. Version 1.28.3 fixes this issue.

Record
EUVD-2026-3297
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-54wq-72mp-cq7c 5.3

Mailpit has an SMTP Header Injection via Regex Bypass

Vulnerability Report: SMTP Header Injection via Regex Bypass

Vulnerable Code: mailpit/internal/smtpd/smtpd.go

Executive Summary

Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate RCPT TO and MAIL FROM addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (\r) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude \r and \n when used inside a character class.

RFC Compliance & Design Analysis

"Is this behavior intentional for a testing tool?" No. While testing tools are often permissive, this specific behavior violates the core SMTP protocol and fails the developer's own intent.

  1. RFC 5321 Violation: The SMTP protocol strictly forbids Control Characters (CR, LF, Null) in the envelope address (Mailbox).
    • RFC 5321 Section 4.1.2: A Mailbox consists of an Atom or Quoted-string. An Atom explicitly excludes "specials, SPACE and CTLs" (Control Characters).
  2. Failed Intent: The existence of \v in the regex [^<>\v] proves the developer intended to block vertical whitespace. The vulnerability is that \v in Go regex (re2) inside brackets [] matches only Vertical Tab, not CR/LF. If the design were to allow everything, the \v exclusion wouldn't exist.
  3. Data Corruption: Allowing \r results in the generation of malformed .eml files where the Received header is broken. This is not a feature; it's a bug that creates invalid email files.
  4. RFC 5321 also enforces address lengths which are not applied in Mailpit.

Technical Analysis

The Flaw

The vulnerability exists in the regex definitions used to parse SMTP commands:

// internal/smtpd/smtpd.go:32-33
rcptToRE   = regexp.MustCompile(`(?i)TO: ?<([^<>\v]+)>( |$)(.*)?`)
mailFromRE = regexp.MustCompile(`(?i)FROM: ?<(|[^<>\v]+)>( |$)(.*)?`)

The developer likely intended [^<>\v] to mean "Match anything that is NOT a < OR > OR Vertical Whitespace".

However, in Go's regexp (RE2) syntax, the behavior of \v changes depending on context:

  • Outside brackets: \v matches all vertical whitespace: [\n\v\f\r\x85\u2028\u2029].
  • Inside brackets ([...]): \v matches only the Vertical Tab character (\x0B).

Result: The regex [^<>\v] allows Carriage Return (\r) and Line Feed (\n) characters to pass through, as they are not < or > or \x0B.

Exploit Scenario

Exploit Scenario

When Mailpit constructs the Received header, it uses the validated recipient address directly:

// internal/smtpd/smtpd.go:865
buffer.WriteString(fmt.Sprintf("        for <%s>; %s\r\n", to[0], now))

If to[0] contains victim\rINJECTED-HEADER: YES, the resulting string in memory becomes:

        for <victim\rINJECTED-HEADER: YES>; ...

While bufio.ReadString prevents injecting immediate \n (newlines), \r (Carriage Return) bypasses this check.

The Result: The stored EML file contains a "Bare CR".

  • RFC Violation: RFC 5321 strictly forbids Bare CR. Lines must end in CRLF.
  • UI Behavior: Browsers typically render Bare CR as a space, so it may look like victim INJECTED in the Mailpit UI.
  • Real Impact: The raw email is corrupted. If this email is exported or relayed, downstream systems (Outlook, older MTAs) may interpret the Bare CR as a line break, triggering a full Header Injection. Furthermore, Mailpit failing to reject this gives developers a false sense of security, as their code might be generating malformed emails that work in Mailpit but fail in production (e.g., with Gmail or Exchange).

Raw EML Verification

The following screenshot of the raw .eml file confirms that the \r character successfully broke the Received header structure in the stored file, effectively creating a new line for the…

Record
GHSA-54wq-72mp-cq7c
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-93, CWE-150
Updated
2026-11-02
NVD 5.3

Mailpit is an email testing tool and API for developers. Prior to version 1.28.3, Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate RCPT TO and MAIL FROM addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (\r) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude \r and \n when used inside a character class. Version 1.28.3 fixes this issue.

Record
CVE-2026-23829
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-93, CWE-150
Updated
2026-11-02
OSV 5.3

Mailpit has SMTP Header Injection via Regex Bypass

Mailpit is an email testing tool and API for developers. Prior to version 1.28.3, Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate RCPT TO and MAIL FROM addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (\r) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude \r and \n when used inside a character class. Version 1.28.3 fixes this issue.

Record
CVE-2026-23829
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-150, CWE-93
Updated
2026-11-02
OSVGHSA-54wq-72mp-cq7c 5.3

Mailpit has an SMTP Header Injection via Regex Bypass

Vulnerability Report: SMTP Header Injection via Regex Bypass

Vulnerable Code: mailpit/internal/smtpd/smtpd.go

Executive Summary

Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate RCPT TO and MAIL FROM addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (\r) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude \r and \n when used inside a character class.

RFC Compliance & Design Analysis

"Is this behavior intentional for a testing tool?" No. While testing tools are often permissive, this specific behavior violates the core SMTP protocol and fails the developer's own intent.

  1. RFC 5321 Violation: The SMTP protocol strictly forbids Control Characters (CR, LF, Null) in the envelope address (Mailbox).
    • RFC 5321 Section 4.1.2: A Mailbox consists of an Atom or Quoted-string. An Atom explicitly excludes "specials, SPACE and CTLs" (Control Characters).
  2. Failed Intent: The existence of \v in the regex [^<>\v] proves the developer intended to block vertical whitespace. The vulnerability is that \v in Go regex (re2) inside brackets [] matches only Vertical Tab, not CR/LF. If the design were to allow everything, the \v exclusion wouldn't exist.
  3. Data Corruption: Allowing \r results in the generation of malformed .eml files where the Received header is broken. This is not a feature; it's a bug that creates invalid email files.
  4. RFC 5321 also enforces address lengths which are not applied in Mailpit.

Technical Analysis

The Flaw

The vulnerability exists in the regex definitions used to parse SMTP commands:

// internal/smtpd/smtpd.go:32-33
rcptToRE   = regexp.MustCompile(`(?i)TO: ?<([^<>\v]+)>( |$)(.*)?`)
mailFromRE = regexp.MustCompile(`(?i)FROM: ?<(|[^<>\v]+)>( |$)(.*)?`)

The developer likely intended [^<>\v] to mean "Match anything that is NOT a < OR > OR Vertical Whitespace".

However, in Go's regexp (RE2) syntax, the behavior of \v changes depending on context:

  • Outside brackets: \v matches all vertical whitespace: [\n\v\f\r\x85\u2028\u2029].
  • Inside brackets ([...]): \v matches only the Vertical Tab character (\x0B).

Result: The regex [^<>\v] allows Carriage Return (\r) and Line Feed (\n) characters to pass through, as they are not < or > or \x0B.

Exploit Scenario

Exploit Scenario

When Mailpit constructs the Received header, it uses the validated recipient address directly:

// internal/smtpd/smtpd.go:865
buffer.WriteString(fmt.Sprintf("        for <%s>; %s\r\n", to[0], now))

If to[0] contains victim\rINJECTED-HEADER: YES, the resulting string in memory becomes:

        for <victim\rINJECTED-HEADER: YES>; ...

While bufio.ReadString prevents injecting immediate \n (newlines), \r (Carriage Return) bypasses this check.

The Result: The stored EML file contains a "Bare CR".

  • RFC Violation: RFC 5321 strictly forbids Bare CR. Lines must end in CRLF.
  • UI Behavior: Browsers typically render Bare CR as a space, so it may look like victim INJECTED in the Mailpit UI.
  • Real Impact: The raw email is corrupted. If this email is exported or relayed, downstream systems (Outlook, older MTAs) may interpret the Bare CR as a line break, triggering a full Header Injection. Furthermore, Mailpit failing to reject this gives developers a false sense of security, as their code might be generating malformed emails that work in Mailpit but fail in production (e.g., with Gmail or Exchange).

Raw EML Verification

The following screenshot of the raw .eml file confirms that the \r character successfully broke the Received header structure in the stored file, effectively creating a new line for the…

Record
GHSA-54wq-72mp-cq7c
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-150, CWE-93
Updated
2026-11-02
OSVGO-2026-4333 No score

Mailpit has an SMTP Header Injection via Regex Bypass in github.com/axllent/mailpit

Mailpit has an SMTP Header Injection via Regex Bypass in github.com/axllent/mailpit

Record
GO-2026-4333
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-2026:0403-1 No score

Security update for govulncheck-vulndb

This update for govulncheck-vulndb fixes the following issues:

  • Update to version 0.0.20260205T172317 2026-02-05T17:23:17Z. Refs jsc#PED-11136 Go CVE Numbering Authority IDs added or updated with aliases:

    • GO-2026-4337 CVE-2025-68121
    • GO-2026-4357 CVE-2026-23954 GHSA-7f67-crqm-jgh7
    • GO-2026-4359 CVE-2026-23953 GHSA-x6jc-phwx-hp32
    • GO-2026-4395 CVE-2026-25499 GHSA-gwch-7m8v-7544
    • GO-2026-4396 CVE-2026-25059 GHSA-qmj2-8r24-xxcq
    • GO-2026-4397 CVE-2026-25060 GHSA-wf93-3ghh-h389
    • GO-2026-4398 GHSA-grh9-37g7-53mj
    • GO-2026-4403 CVE-2025-22873
    • GO-2026-4404 CVE-2025-70849 GHSA-mw8w-q3f7-2v85
    • GO-2026-4405 CVE-2026-25121 GHSA-5g94-c2wx-8pxw
    • GO-2026-4406 CVE-2026-25122 GHSA-6p9p-q6wh-9j89
    • GO-2026-4407 CVE-2026-24843 GHSA-qxx2-7h4c-83f4
    • GO-2026-4408 CVE-2026-24844 GHSA-vqqr-rmpc-hhg2
    • GO-2026-4409 CVE-2026-25145 GHSA-2w4f-9fgg-q2v9
    • GO-2026-4411 CVE-2026-25579 GHSA-hrr4-3wgr-68x3
    • GO-2026-4412 CVE-2026-25143 GHSA-rf4g-89h5-crcr
    • GO-2026-4413 CVE-2026-25578 GHSA-rh3r-8pxm-hg4w
    • GO-2026-4414 CVE-2026-25160 GHSA-8jmm-3xwx-w974
    • GO-2026-4415 CVE-2026-25161 GHSA-x4q4-7phh-42j9
    • GO-2026-4416 CVE-2026-25538 GHSA-8wpc-j9q9-j5m2
    • GO-2026-4417 CVE-2026-24514 GHSA-2pf9-vr92-6h3v
    • GO-2026-4418 CVE-2023-43631 GHSA-3mq9-xhgq-r7gj
    • GO-2026-4419 CVE-2026-24513 GHSA-4g2f-xcph-2335
    • GO-2026-4421 CVE-2026-24735 GHSA-5w5r-8xc6-2xhw
    • GO-2026-4422 CVE-2023-43632 GHSA-6jp5-grgh-jw42
    • GO-2026-4423 CVE-2026-1580 GHSA-9h3p-52vh-959w
    • GO-2026-4425 CVE-2025-62878 GHSA-jr3w-9vfr-c746
    • GO-2026-4426 CVE-2026-24512 GHSA-jx8c-56mg-h6vp
    • GO-2026-4428 CVE-2023-43633 GHSA-4c4v-42hc-72p6
    • GO-2026-4430 CVE-2023-43630 GHSA-phcg-h58r-gmcq
    • GO-2026-4432 CVE-2023-43634 GHSA-wc42-fcjp-v8vq
    • GO-2026-4433 CVE-2025-61732
    • GO-2026-4440 CVE-2025-47911
    • GO-2026-4441 CVE-2025-58190

  • Update to version 0.0.20260204T190754 2026-02-04T19:07:54Z. Refs jsc#PED-11136 Go CVE Numbering Authority IDs added or updated with aliases:

    • GO-2026-4324 CVE-2026-23645 GHSA-pcjq-j3mq-jv5j
    • GO-2026-4327 CVE-2026-23742 GHSA-cc8m-98fm-rc9g
    • GO-2026-4329 CVE-2026-21696 GHSA-2497-gp99-2m74
    • GO-2026-4330 CVE-2026-22822 GHSA-77v3-r3jw-j2v2
    • GO-2026-4331 CVE-2025-69199 GHSA-8w7m-w749-rx98
    • GO-2026-4333 CVE-2026-23829 GHSA-54wq-72mp-cq7c
    • GO-2026-4334 CVE-2026-23517 GHSA-4r5r-ccr6-q6f6
    • GO-2026-4335 CVE-2026-23518 GHSA-63m5-974w-448v
    • GO-2026-4336 CVE-2026-22808 GHSA-gfpw-jgvr-cw4j
    • GO-2026-4343 CVE-2026-23847 GHSA-w836-5gpm-7r93
    • GO-2026-4344 CVE-2026-23849 GHSA-43mm-m3h2-3prc
    • GO-2026-4345 CVE-2026-23845 GHSA-6jxm-fv7w-rw5j
    • GO-2026-4346 CVE-2026-23851 GHSA-94c7-g2fj-7682
    • GO-2026-4347 CVE-2026-23850 GHSA-cv54-7wv7-qxcw
    • GO-2026-4348 CVE-2026-23991 GHSA-846p-jg2w-w324
    • GO-2026-4349 CVE-2026-23992 GHSA-fphv-w9fq-2525
    • GO-2026-4350 CVE-2026-23960 GHSA-cv78-6m8q-ph82
    • GO-2026-4351 CVE-2026-23990 GHSA-4xh5-jcj2-ch8q
    • GO-2026-4352 GHSA-r92c-9c7f-3pj8
    • GO-2026-4353 CVE-2026-24058 GHSA-pchf-49fh-w34r
    • GO-2026-4354 CVE-2026-23831 GHSA-273p-m2cw-6833
    • GO-2026-4355 CVE-2026-24117 GHSA-4c4x-jm2x-pf9j
    • GO-2026-4356 CVE-2026-24124 GHSA-j8hf-cp34-g4j7
    • GO-2026-4362 CVE-2026-20800 GHSA-2vgv-hgv4-22mh
    • GO-2026-4363 CVE-2026-20897 GHSA-393c-qgvj-3xph
    • GO-2026-4364 CVE-2026-20912 GHSA-4xx9-vc8v-87hv
    • GO-2026-4365 CVE-2026-0798 GHSA-8fwc-qjw5-rvgp
    • GO-2026-4366 CVE-2026-20888 GHSA-9cgq-wp42-4rpq
    • GO-2026-4367 CVE-2026-20736 GHSA-hgr3-x44x-33hx
    • GO-2026-4368 CVE-2026-20883 GHSA-j8xr-c56q-m8jj
    • GO-2026-4369 CVE-2026-20904 GHSA-qqgv-v353-cv8p
    • GO-2026-4370 CVE-2026-20750 GHSA-rw22-5hhq-pfpf
    • GO-2026-4377 CVE-2026-24686 GHSA-jqc5-w2xx-5vq4
    • GO-2026-4378 CVE-2026-24470 GHSA-mxxc-p822-2hx9
    • GO-2026-4379 CVE-2026-24738 GHSA-j49h-6577-5xwq
    • GO-2026-4380 CVE-2026-24740 GHSA-m855-r557-5rc5
    • GO-2026-4381 CVE-2026-22039 GHSA-8p9x-46gm-qfx2
    • GO-2026-4382 CVE-2026-23881 GHSA-r2rj-wwm5-x6mq
    • GO-2026-4384…
Record
SUSE-SU-2026:0403-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
github.com/axllent/mailpit
Go
 through 1.28.2
1.28.3
github.com/axllent/mailpit
Go
 before 1.28.3
1.28.3
govulncheck-vulndb
openSUSE:Leap 15.6
From an advisory covering 76 CVEs
 before 0.0.20260205T172317-150000.1.146.1
0.0.20260205T172317-150000.1.146.1
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

Public exploits

Links only. Every CVE stores no exploit code.

Public exploits
SourceLinkDate
PoC in GitHubSimoesCTT/CTT-Mailpit-RCE-v1.0---Temporal-Resonance-Mail-Server-Takeover2026-01-28
PoC in GitHubSimoesCTT/-CVE-2026-23829-CTT-Mailpit-phase-reconstruction-2026-02-19
NucleiMailpit < 1.28.2 - SMTP CRLF Injection

History

History
RecordedChangedSources
affected, exploits, facts
first indexedCVE List, EUVD, GitHub Advisories, Nuclei, NVD, OSV, PoC in GitHub

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

In short

CVE-2026-23829 is a medium vulnerability (CVSS 5.3) in Axllent Mailpit, published January 18, 2026. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 1.40%, the 72nd percentile. Fixed in github.com/axllent/mailpit 1.28.3.

References

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Left out here: 1,542 references and the rest of 4 source descriptions. The JSON record has them.

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