---
id: CVE-2026-4426
title: A flaw was found in libarchive
summary: >-
  A flaw was found in libarchive. An Undefined Behavior vulnerability exists in
  the zisofs decompression logic, caused by improper validation of a field
  (`pz_log2_bs`) read from ISO9660 Rock Ridge extensions. A remote attacker can
  exploit …
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'
cwe:
  - CWE-1335
vendor: libarchive
product: libarchive
affected:
  - libarchive
  - hardened_images
  - openshift_container_platform = 4.0
  - enterprise_linux = 6.0
  - enterprise_linux = 7.0
  - enterprise_linux = 8.0
  - enterprise_linux = 9.0
  - enterprise_linux = 10.0
published: '2026-03-19'
updated: '2026-08-21'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-4426'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:8944'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-4426'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2449010'
    label: secalert@redhat.com
  - url: 'https://github.com/libarchive/libarchive/pull/2897'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.0056
epssPercentile: 0.44214
ingestedAt: '2026-08-21T14:17:57.332Z'
---

## Overview

A flaw was found in libarchive. An Undefined Behavior vulnerability exists in the zisofs decompression logic, caused by improper validation of a field (`pz_log2_bs`) read from ISO9660 Rock Ridge extensions. A remote attacker can exploit this by supplying a specially crafted ISO file. This can lead to incorrect memory allocation and potential application crashes, resulting in a denial-of-service (DoS) condition.

## Affected

- `libarchive`
- `hardened_images`
- `openshift_container_platform = 4.0`
- `enterprise_linux = 6.0`
- `enterprise_linux = 7.0`
- `enterprise_linux = 8.0`
- `enterprise_linux = 9.0`
- `enterprise_linux = 10.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.