apt 0.8.16, 0.9.7, and possibly other versions does not properly handle InRelease files, which allows man-in-the-middle attackers to modify packages before installation via unknown vectors, possibly related to integrity checking and the use of third-party repositories.

Apt 0.8.16~exp5ubuntu13.x before 0.8.16~exp5ubuntu13.6, 0.8.16~exp12ubuntu10.x before 0.8.16~exp12ubuntu10.7, and 0.9.7.5ubuntu5.x before 0.9.7.5ubuntu5.2, as used in Ubuntu, uses world-readable permissions for /var/log/apt/term.log, which allows local users to obtain sensitive shell information by reading the log file.

Debian and Ubuntu APT Flaw Enables Remote Root Code Execution Through Malicious HTTP Traffic.

Fixes are available for CVE-2026-109518, a High severity vulnerability in APT, the package manager used in Debian, Ubuntu, and derivative Linux distributions. The CVE has a CVSS 4.0 score of 7.7.