CVE-2026-40684
CVSS Score
5.9
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-684 |
| Vendor | exim |
| Product | exim |
| Published | Apr 30, 2026 |
| Last Updated | Apr 30, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
Exim / Exim
0 < 4.99.2
References
exim.org: https://exim.org/static/doc/security/CVE-2025-40684.txt openwall.com: https://www.openwall.com/lists/oss-security/2026/04/30/21 exim.org: https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40684.assessment code.exim.org: https://code.exim.org/exim/exim/commit/628bbaca7672748d941a12e7cd5f0122a4e18c81