CVE-2026-40686

State: Published
Severity: 3.7 Low
Published: Apr 30, 2026
Updated: May 1, 2026
Reserved: Apr 14, 2026

Description

In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.

Scores

CVSS	Score	Vector	Source
3.1	3.7 Low	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N	mitre

Weaknesses

CWE-125 Out-of-bounds Read

Affected Products

Product	Versions
EximExim	before 4.99.2Affected

References

https://www.openwall.com/lists/oss-security/2026/04/30/21
https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessment
https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc
https://exim.org/static/doc/security/CVE-2026-40686.txt

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