Input validation error in Exim - CVE-2026-40684
Published: May 7, 2026
Vulnerability identifier: #VU130454
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-40684
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Exim
Affected software:
Exim
Exim
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper handling of malformed DNS data in PTR record processing when processing DNS responses on systems using musl libc. A remote attacker can provide specially crafted DNS data to cause a denial of service.
Only systems using musl libc are affected.
How to mitigate CVE-2026-40684
Install security update from vendor's website.