Vulnerability in Libarchive
CVE-2026-4426
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (46.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 46.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.006 · change: +0.003
Affected products
Weakness classification (CWE)
References
- access.redhat.com/errata/RHSA-2026:8944 (vendor-advisory)
- access.redhat.com/security/cve/CVE-2026-4426 (Third Party Advisory, vdb-entry)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking, Third Party Advisory, Issue Tracking)
- github.com/libarchive/libarchive/pull/2897 (Patch, Issue Tracking)
Frequently asked questions
- What is CVE-2026-4426?
- CVE-2026-4426 is a medium-severity vulnerability in Libarchive, classified under CWE-1335. CVSS score: 6.5/10. Published 2026-03-19.
- How severe is CVE-2026-4426?
- Medium severity. CVSS v3 base score is 6.5 out of 10.