CVE-2026-40684
- State
- Published
- Severity
- 5.9 Medium
- Published
- Apr 30, 2026
- Updated
- May 1, 2026
- Reserved
- Apr 14, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | mitre |
Weaknesses
- CWE-684 Incorrect Provision of Specified Functionality
Affected Products
| Product | Versions |
|---|---|
EximExim |
|
References
- https://www.openwall.com/lists/oss-security/2026/04/30/21
- https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40684.assessment
- https://code.exim.org/exim/exim/commit/628bbaca7672748d941a12e7cd5f0122a4e18c81
- https://exim.org/static/doc/security/CVE-2026-40684.txt
- http://www.openwall.com/lists/oss-security/2026/05/01/11
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