CVE-2026-40686

Published: Apr 30, 2026Modified: Jun 17, 2026

5.3

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Exploitability: 3.9 / Impact: 1.4

Source: NVD

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.

Affected (1)

Products: Exim: Exim

1 product

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Exim Exim	Before 4.99.2

Related CWEs

Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

References (4)

https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc

Source: cve@mitre.org

Patch

https://exim.org/static/doc/security/CVE-2026-40686.txt

Source: cve@mitre.org

Broken Link

https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessment

Source: cve@mitre.org

Vendor Advisory

https://www.openwall.com/lists/oss-security/2026/04/30/21

Source: cve@mitre.org

Mailing ListThird Party Advisory

Timeline

No history available yet.