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Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : opam vulnerability (USN-8256-1)

high Nessus Plugin ID 314209

Synopsis

The remote Ubuntu host is missing a security update.

Description

The remote Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-8256-1 advisory.

 Andrew Nesbitt discovered that opam did not properly validate file destination paths in package install files. An attacker could use this issue to bypass sandbox protections and write files to arbitrary locations, possibly leading to arbitrary code execution.

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 opam and / or opam-installer packages.

See Also

https://ubuntu.com/security/notices/USN-8256-1

Plugin Details

Severity: High

ID: 314209

File Name: ubuntu_USN-8256-1.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 5/11/2026

Updated: 5/11/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.7

CVSS v2

Risk Factor: Medium

Base Score: 6.1

Temporal Score: 4.5

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

CVSS Score Source: CVE-2026-41082

CVSS v3

Risk Factor: High

Base Score: 7.3

Temporal Score: 6.4

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:opam-installer, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:25.10, p-cpe:/a:canonical:ubuntu_linux:opam, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/7/2026

Vulnerability Publication Date: 4/16/2026

Reference Information

CVE: CVE-2026-41082

USN: 8256-1