Quick answers
- Is CVE-2026-4426 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-4426 being exploited in the wild.
- How severe is CVE-2026-4426?
- Medium severity, with a CVSS score of 6.5, published 19 March 2026.
- Which products and versions are affected?
- Libarchive <UNKNOWN>.
- Is there a fix for CVE-2026-4426?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-4426 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-4426?
- Check whether you run Libarchive at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
An undefined behavior vulnerability exists in libarchive's zisofs decompression logic, caused by improper validation of the `pz_log2_bs` field read from ISO9660 Rock Ridge extensions. The vulnerability can be triggered by supplying a specially crafted ISO file with invalid field values. This leads to incorrect memory allocation calculations, causing application crashes and denial-of-service conditions. The flaw is reachable remotely via processing untrusted ISO files, with no authentication or user interaction required beyond opening the file. Patches addressing this validation issue are expected from the libarchive maintainers.
Affected products
- libarchive libarchive <UNKNOWN>
Timeline
- 2026-03-19: disclosed