PT-2026-79204 · Mailpit · Mailpit

CVE-2026-67447

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Published

2026-08-20

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Updated

2026-09-04

CVSS v3.1

5.3

Medium

VectorAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Name of the Vulnerable Software and Affected Versions Mailpit versions 1.30.0 through 1.30.4
Description An unauthenticated SMTP client can cause substantial memory pressure by sending a single line that exceeds the configured MaxMessageSize. This occurs because the readData() function in internal/smtpd/smtpd.go calls bufio.Reader.ReadBytes before validating the combined size of data and line against Server.MaxSize. Consequently, the full line is allocated in memory before the system returns a 552 5.3.4 rejection.
Recommendations Update to version 1.30.5.

Exploit

Fix

Allocation of Resources Without Limits

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Weakness Enumeration

Related Identifiers

CVE-2026-67447
GHSA-R553-M4FV-5V97
GO-2026-6272
OPENSUSE-SU-2026:21761-1

Affected Products

Mailpit