CVE-2026-67447
MEDIUM 5.3EPSS 0.4%
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 v3.1
- 5.3 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - CVSS v3.1
- 5.3 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - EPSS
- 0.37% chance of exploitation in the next 30 days, 30th percentile
- Published
- 2026-08-20
- Updated
- 2026-08-21