Distribution advisory
This page covers CVE-2026-66140 as tracked by Debian 12 (Root.io), for the package exim4. The fix is available in version 4.96-15+deb12u10.aikido.2; earlier versions remain affected.
How this vulnerability can be exploited
This issue can be reached with local access to the system, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high. (rating taken from the base CVE record.)
CVSS metrics in full
The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Attack vector: Local — a local account, shell or session on the host is needed.
- Attack complexity: Low — the attack works reliably, with no preparation.
- Privileges required: None — an unauthenticated stranger can try it.
- User interaction: None — nobody has to be tricked into anything.
- Scope: Unchanged — the damage stays inside the vulnerable component.
- Confidentiality impact: High — total loss, or loss the attacker controls.
- Integrity impact: High — total loss, or loss the attacker controls.
- Availability impact: High — total loss, or loss the attacker controls.
Weakness class
ROOT-OS-DEBIAN-12-CVE-2026-66140 is classified as CWE-24: Path Traversal: '../filedir'. The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize "../" sequences that can resolve to a location that is outside of that directory.
Affected software
ROOT-OS-DEBIAN-12-CVE-2026-66140 is recorded against 2 packages.
- exim4 (fixed in 4.96-15+deb12u10.aikido.2)
- rootio-exim4 (fixed in 4.96-15+deb12u10.aikido.2)
Timeline and source
Published on 5 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
Other advisories for this package
exim4 has other advisories on record. If you are patching this one, these are worth checking on the same host:
Same weakness in other software
These advisories are the same class of weakness (CWE-24: Path Traversal: '../filedir') in other software:
