CVE-2026-67447Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement
Updated under an hour ago ()
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It affects axllent mailpit. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Mailpit is an email testing tool and API for developers. From 1.30.0 until 1.30.5, Mailpit's internal/smtpd/smtpd.go readData() function calls bufio.Reader.ReadBytes before applying the len(data)+len(line) size check to the completed SMTP DATA line against Server.MaxSize. An unauthenticated SMTP client can send a single line larger than the configured MaxMessageSize, causing the full line to be allocated before Mailpit returns the 552 5.3.4 rejection. This post-fix gap remains after normal multi-line DATA accumulation was bounded, and concurrent oversized lines can create substantial memory pressure beyond the configured message-size cap. This issue is fixed in version 1.30.5.
- CVSS
- 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Weakness (CWE)
- CWE-770
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Aug 21, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
axllent mailpit axllent:mailpit (from the name) | from 1.30.0, < 1.30.5 | CNA record |
References
- https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97x-refsource-confirm
- https://github.com/axllent/mailpit/commit/8720c6bd8281fc00d458081908f1dbef8e59a98cx-refsource-misc
- https://github.com/axllent/mailpit/releases/tag/v1.30.5x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.