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CVE-2026-109518

HIGHCVSS 7.7/10

Last modified

CVE-2026-109518 is a high-severity vulnerability rated 7.7/10 on the CVSS scale. 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.

Description

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

Metrics

CVSS 4.0
7.7/10

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
DebianAPT< 1.2.36; >= 1.4.0, < 1.4.12; >= 1.6.0, < 1.6.19; >= 1.8.0, < 1.8.2.4; >= 1.8.3, <= 1.8.5; >= 2.0.0, < 2.0.12; >= 2.2.0, < 2.2.5; >= 2.4.0, < 2.4.15; >= 2.6.0, < 2.6.2; >= 2.8.0, < 2.8.4; >= 3.0.0, < 3.0.4; >= 3.2.0, < 3.2.1; >= 3.3.0, < 3.3.6
UbuntuAPT< 1.0.1ubuntu2.24+esm4; >= 1.2.0, < 1.2.36+esm1; >= 1.6.0, < 1.6.19+esm1; >= 2.0.0, < 2.0.12+esm1; >= 2.4.0, < 2.4.15ubuntu0.1; >= 2.8.0, < 2.8.4ubuntu0.1; >= 3.2.0, < 3.2.1ubuntu0.1; >= 3.3.0, < 3.3.3ubuntu0.1

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is 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
How severe is CVE-2026-109518?
CVE-2026-109518 has a CVSS score of 7.7/10 (HIGH severity).
How do I fix CVE-2026-109518?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST