CVE-2026-40684

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

7.5

Vector

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

Exploitability: 3.9 / Impact: 3.6

Source: NVD

Description

In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the connection instance when malformed DNS data is present in PTR records. This is caused by a dn_expand oddity in octal printing.

Affected (1)

Products: Exim: Exim

Exim

1 product

Exim

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Exim Exim	Before 4.99.2

Related CWEs

CWE-684

Incorrect Provision of Specified Functionality

The code does not function according to its published specifications, potentially leading to incorrect usage.

References (5)

https://code.exim.org/exim/exim/commit/628bbaca7672748d941a12e7cd5f0122a4e18c81

Source: cve@mitre.org

Patch

https://exim.org/static/doc/security/CVE-2026-40684.txt

Source: cve@mitre.org

Broken Link

https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40684.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

http://www.openwall.com/lists/oss-security/2026/05/01/11

Source: af854a3a-2127-422b-91ae-364da2661108

Timeline

No history available yet.