Debian and Ubuntu APT Flaw Lets MitM Attackers Swap Verified Packages and Run Code as Root
A flaw in APT , the package manager for Debian and Ubuntu, allows an attacker who can modify package downloads to swap a checked package for their own. The attacker's code then runs as root, according to advisories that Debian , Ubuntu , and APT's developers published on November 4. The attack needs APT to retry failed downloads, which it does by default from Debian 12 and Ubuntu 22.04 onward. Debian has released fixed versions of APT for the flaw, CVE-2026-109518 . APT's developers, who call the flaw critical, say updates for Ubuntu and its Ubuntu Pro subscription service are being released. Ubuntu 14.04 users with Ubuntu Pro can already get one. Older releases, such as Debian 11 and Ubuntu 20.04, are not exposed by default, according to Ubuntu. But many user scripts may have turned on the retry setting, Acquire::Retries, on those releases anyway, APT's developers say. Debian's testing branch was still on the vulnerable version 3.3.5 at...
Nov 04, 2026