APT RCE via hard link reuse
Summary
| CVE | CVE-2026-109518 |
|---|---|
| State | PUBLISHED |
| Assigner | canonical |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-11-04 16:17:33 UTC |
| Updated | 2026-11-05 05:18:19 UTC |
| 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 |
Risk And Classification
Primary CVSS: v4.0 7.7 HIGH from [email protected]
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
Problem Types: CWE-62 | CWE-367 | CWE-62 CWE-62 UNIX hard link | CWE-367 CWE-367 Time-of-check time-of-use (TOCTOU) race condition
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 7.7 | HIGH | 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/C... |
| 4.0 | CNA | CVSS | 7.7 | HIGH | 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 |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
NoneUser Interaction
PassiveConfidentiality
HighIntegrity
HighAvailability
HighSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS: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
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Debian | APT | affected 1.2.36 dpkg | Not specified |
| CNA | Debian | APT | affected 1.4.0 1.4.12 dpkg | Not specified |
| CNA | Debian | APT | affected 1.6.0 1.6.19 dpkg | Not specified |
| CNA | Debian | APT | affected 1.8.0 1.8.2.4 dpkg | Not specified |
| CNA | Debian | APT | affected 1.8.3 1.8.5 dpkg | Not specified |
| CNA | Debian | APT | affected 2.0.0 2.0.12 dpkg | Not specified |
| CNA | Debian | APT | affected 2.2.0 2.2.5 dpkg | Not specified |
| CNA | Debian | APT | affected 2.4.0 2.4.15 dpkg | Not specified |
| CNA | Debian | APT | affected 2.6.0 2.6.2 dpkg | Not specified |
| CNA | Debian | APT | affected 2.8.0 2.8.4 dpkg | Not specified |
| CNA | Debian | APT | affected 3.0.0 3.0.4 dpkg | Not specified |
| CNA | Debian | APT | affected 3.2.0 3.2.1 dpkg | Not specified |
| CNA | Debian | APT | affected 3.3.0 3.3.6 dpkg | Not specified |
| CNA | Ubuntu | APT | affected 1.0.1ubuntu2.24+esm4 dpkg | Not specified |
| CNA | Ubuntu | APT | affected 1.2.0 1.2.36+esm1 dpkg | Not specified |
| CNA | Ubuntu | APT | affected 1.6.0 1.6.19+esm1 dpkg | Not specified |
| CNA | Ubuntu | APT | affected 2.0.0 2.0.12+esm1 dpkg | Not specified |
| CNA | Ubuntu | APT | affected 2.4.0 2.4.15ubuntu0.1 dpkg | Not specified |
| CNA | Ubuntu | APT | affected 2.8.0 2.8.4ubuntu0.1 dpkg | Not specified |
| CNA | Ubuntu | APT | affected 3.2.0 3.2.1ubuntu0.1 dpkg | Not specified |
| CNA | Ubuntu | APT | affected 3.3.0 3.3.3ubuntu0.1 dpkg | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.openwall.com/lists/oss-security/2026/11/04/12 | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | |
| lists.debian.org/debian-security-announce/2026/msg00526.html | [email protected] | lists.debian.org | |
| ubuntu.com/security/notices/USN-8996-1 | [email protected] | ubuntu.com | |
| lists.debian.org/debian-lts-announce/2026/11/msg00004.html | af854a3a-2127-422b-91ae-364da2661108 | lists.debian.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Max Justicz (en)
CNA: Julian Andres Klode (en)
There are currently no legacy QID mappings associated with this CVE.