Linux Distros Unpatched Vulnerability : CVE-2026-96808

high Nessus Plugin ID 349599

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- In Flatpak before 1.18.1, the revokefs writer, used by the flatpak-system-helper to receive repository data from unprivileged callers, validated file paths by rejecting literal .. components but did not prevent symlink traversal. A malicious local user in an active local session could obtain two revokefs sessions via the system helper, create a symlink in one session pointing into the other session's directory, and retain a file descriptor through that symlink. This allowed the attacker to modify files belonging to a different revokefs session after they had been validated and imported by the system helper.
In particular, an attacker could use this to tamper with ostree commit objects in the system repository after they passed signature verification, enabling root-controlled file writes to attacker-chosen paths and local root privilege escalation. (CVE-2026-96808)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: High

ID: 349599

File Name: unpatched_CVE_2026_96808.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Misc.

Published: 9/24/2026

Updated: 9/24/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.29

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.9

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

CVSS Score Source: CVE-2026-96808

CVSS v3

Risk Factor: High

Base Score: 7.4

Temporal Score: 6.8

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

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

Vulnerability Information

CPE: cpe:/o:centos:centos:7, cpe:/o:centos:centos:8, cpe:/o:debian:debian_linux:12.0, cpe:/o:redhat:enterprise_linux:10, cpe:/o:redhat:enterprise_linux:7, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:centos:centos:flatpak-builder, p-cpe:/a:centos:centos:flatpak-devel, p-cpe:/a:centos:centos:flatpak-libs, p-cpe:/a:centos:centos:flatpak-selinux, p-cpe:/a:centos:centos:flatpak-session-helper, p-cpe:/a:centos:centos:flatpak, p-cpe:/a:debian:debian_linux:flatpak, p-cpe:/a:redhat:enterprise_linux:flatpak-builder, p-cpe:/a:redhat:enterprise_linux:flatpak-devel, p-cpe:/a:redhat:enterprise_linux:flatpak-libs, p-cpe:/a:redhat:enterprise_linux:flatpak-selinux, p-cpe:/a:redhat:enterprise_linux:flatpak-session-helper, p-cpe:/a:redhat:enterprise_linux:flatpak

Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 9/23/2026

Reference Information

CVE: CVE-2026-96808

Detections

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