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.
Project Subscriptions
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Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-r553-m4fv-5v97 | Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 20 Aug 2026 21:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement | |
| Weaknesses | CWE-770 | |
| References |
| |
| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-08-20T21:15:06.567Z
Reserved: 2026-07-29T15:07:24.992Z
Link: CVE-2026-67447
No data.
Status : Received
Published: 2026-08-20T22:17:56.720
Modified: 2026-08-20T22:17:56.720
Link: CVE-2026-67447
No data.
OpenCVE Enrichment
No data.
Weaknesses
Github GHSA