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Ubuntu 20.04 LTS / 26.04 LTS : libgit2 vulnerability (USN-8809-1)

high Nessus Plugin ID 349786

Synopsis

The remote Ubuntu host is missing a security update.

Description

The remote Ubuntu 20.04 LTS / 26.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-8809-1 advisory.

 Kazuma Matsumoto and Isabel Mill discovered that libgit2 incorrectly handled certain repository URLs when using the SSH transport. A remote attacker could possibly use this issue to execute arbitrary commands.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected libgit2-1.9, libgit2-28 and / or libgit2-fixtures packages.

See Also

https://ubuntu.com/security/notices/USN-8809-1

Plugin Details

Severity: High

ID: 349786

File Name: ubuntu_USN-8809-1.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 9/24/2026

Updated: 9/24/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.17

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-5917

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 7.7

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: High

Base Score: 8.6

Threat Score: 6.1

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libgit2-1.9, p-cpe:/a:canonical:ubuntu_linux:libgit2-28, p-cpe:/a:canonical:ubuntu_linux:libgit2-fixtures

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 9/23/2026

Vulnerability Publication Date: 8/11/2026

Reference Information

CVE: CVE-2026-5917

USN: 8809-1