Answer in brief
CVE-2026-67447 records a Medium severity (CVSS 5.3) vulnerability in Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement. The current sources do not mark it as known exploited. The current feed maps axllent/mailpit (generic), github.com/axllent/mailpit (go), github.com/axllent/mailpit (go). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps axllent/mailpit (generic), github.com/axllent/mailpit (go), github.com/axllent/mailpit (go). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| axllent/mailpitgeneric | >=1.30.0 <1.30.5 | 1.30.5 |
| github.com/axllent/mailpitgo | >=1.30.0,<1.30.5 | 1.30.5 |
| github.com/axllent/mailpitgo | >=1.30.0 <1.30.5 | 1.30.5 |
Published upstream
Aug 20, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 18, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 20, 2026
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.
Quoted source text, attributed separately from HOL analysis.