CVE-2026-109518
On Debian, Ubuntu, and derivative Linux distributions, an on-path attacker who can manipulate the HTTP traffic (including a malicious mirror or proxy) between an APT client and an archive server triggered by a package install can trick the client into installing an attacker-controlled unverified package and achieve remote code execution with root privileges. The vulnerability is caused by the reuse of hard links and requires the client to follow redirects and retry the download of package files. It requires the client to have a non-zero Acquire::Retries configuration setting; the value 3 is the default starting with Debian 12 (bookworm) and Ubuntu 22.04 LTS (Jammy Jellyfish), so older releases are unaffected in a default configuration
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- Published by NVD
- Last updated by NVD
- First covered by RedTeamDaily
Coverage
Debian APT flaw CVE-2026-109518 lets attackers hijack updates and run code as root
CVE-2026-109518 is a flaw in APT that can let a man-in-the-middle replace a verified package during an interrupted, redirected download, leading to code execution as root. It requires the attacker to sit on the network path and APT's Acquire::Retries setting to be above zero, which is 3 by default on Debian 12 and Ubuntu 22.04 LTS. Debian's fixes are APT 2.6.2 for bookworm and 3.0.4 for trixie, and Ubuntu and other derivatives need their own patches.
Sources: NVD and CISA known exploited vulnerabilities catalogue.