UBUNTU-CVE-2026-109518

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    UBUNTU-CVE-2026-109518

    Published: 4 Nov 2026Last Modified: 5 Nov 2026
    Upstream:
    CVE-2026-109518
    Aliases:
    USN-8996-1

    Summary:

    Details: 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.

    References: https://ubuntu.com/security/CVE-2026-109518, https://www.cve.org/CVERecord?id=CVE-2026-109518, https://ubuntu.com/blog/apt-vulnerability-fixes-available, https://ubuntu.com/security/notices/USN-8996-1

    Affected packages

    Package

    Name: apt

    Purl: pkg:deb/ubuntu/apt?arch=source&distro=esm-infra-legacy%2Ftrusty

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -1.0.1ubuntu2.24+esm4

    Affected versions

    0.9.9.1~ubuntu3
    0.9.9.1~ubuntu4
    0.9.9.1~ubuntu5
    0.9.13~exp1ubuntu1
    0.9.13~exp1ubuntu2
    0.9.13~exp1ubuntu3
    0.9.13.1~ubuntu1
    0.9.14.1ubuntu1
    0.9.14.1ubuntu2
    0.9.15.1ubuntu1
    0.9.15.4ubuntu1
    0.9.15.4ubuntu2
    0.9.15.4ubuntu3
    0.9.15.4ubuntu4
    0.9.15.4ubuntu5

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    UBUNTU-CVE-2026-109518 | CVE-DB