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CVE-2026-4426 Red Hat CVE debrief

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-03-19T15:16:28.510Z and has not been modified since then. The NVD entry is currently Modified. The CVE-2026-4426 vulnerability exists in libarchive's 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 vulnerability by supplying a specially crafted ISO file, potentially leading to incorrect memory allocation and application crashes, resulting in a denial-of-service (DoS) condition. This flaw can impact systems utilizing libarchive or related components, particularly affecting Red Hat Enterprise Linux users. System administrators and security teams should assess their exposure and apply vendor patches or updates as available. Implementing compensating controls, such as monitoring for suspicious ISO file processing activities, is also recommended. Evidence is based on official CVE and NVD records, as well as references from Red Hat. The vulnerability has a CVSS score of 6.5 and is classified as Medium severity, indicating a need for medium-priority defensive actions.

Vendor
Red Hat
Product
Red Hat Hardened Images
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-03-19
Original CVE updated
2026-08-21
Advisory published
2026-03-19
Advisory updated
2026-08-21

Who should care

System administrators and security teams responsible for systems utilizing libarchive or related components should be aware of this vulnerability. Red Hat Enterprise Linux users are particularly affected, as noted in the CVE and NVD records.

Technical summary

The CVE-2026-4426 vulnerability exists in libarchive's zisofs decompression logic. It is caused by improper validation of a field (`pz_log2_bs`) read from ISO9660 Rock Ridge extensions. A remote attacker can exploit this vulnerability by supplying a specially crafted ISO file, which can lead to incorrect memory allocation and potential application crashes, resulting in a denial-of-service (DoS) condition. The vulnerability has a CVSS score of 6.5 and is classified as Medium severity.

Defensive priority

Medium-priority defensive actions are recommended due to the potential for denial-of-service (DoS) conditions.

Recommended defensive actions

  • Inventory and assess systems for exposure to libarchive and related components.
  • Apply vendor patches or updates as available.
  • Implement compensating controls such as monitoring for suspicious ISO file processing activities.
  • Consider restricting access to untrusted sources of ISO files.
  • Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
  • Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.

Evidence notes

The CVE-2026-4426 flaw exists in libarchive's zisofs decompression logic due to 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, potentially leading to incorrect memory allocation and application crashes, resulting in a denial-of-service (DoS) condition. Evidence is based on official CVE and NVD records, as well as references from Red Hat.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-03-19T15:16:28.510Z and has not been modified since then.