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CVE-2026-56208 Red Hat CVE debrief

CVE-2026-56208 is a high-severity heap buffer overflow vulnerability in libaom, the reference AV1 codec implementation. A flaw in the AV1 encoder's Look-Ahead Processing (LAP) mode causes the first-pass stats ring buffer wrap-around guard to be bypassed when g_lag_in_frames is set to 1 or higher. This results in a 232-byte out-of-bounds write on every encoded frame after the second, corrupting adjacent heap objects. An attacker who can influence encoder configuration in a transcoding service or WebRTC session could exploit this to cause a denial of service (process crash) or potentially achieve code execution. The CVSS score for this vulnerability is 7.6, indicating a high severity. Defenders should prioritize patching this vulnerability to limit exposure to potential attacks.

Vendor
Red Hat
Product
Red Hat Enterprise Linux 10
CVSS
HIGH 7.6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-19
Original CVE updated
2026-09-21
Advisory published
2026-06-19
Advisory updated
2026-09-21

Who should care

Organizations using libaom or products that incorporate libaom, such as video transcoding services or WebRTC applications, should prioritize patching this vulnerability. Additionally, developers who work with AV1 encoding or decoding should be aware of this vulnerability and take steps to ensure that their applications are not exposed to this issue.

Technical summary

The vulnerability is caused by a flaw in the AV1 encoder's Look-Ahead Processing (LAP) mode. When g_lag_in_frames is set to 1 or higher, the first-pass stats ring buffer wrap-around guard is bypassed, resulting in a 232-byte out-of-bounds write on every encoded frame after the second. This corrupts adjacent heap objects, potentially allowing an attacker to cause a denial of service (process crash) or achieve code execution.

Defensive priority

High priority due to potential for code execution and denial of service

Recommended defensive actions

  • Apply patches or updates to libaom to fix the vulnerability
  • Review and update encoder configurations to prevent exploitation
  • Monitor for suspicious activity in transcoding services or WebRTC sessions
  • Implement compensating controls to limit exposure to potential attacks
  • Inventory and track libaom usage in products and applications

Evidence notes

The vulnerability was found in libaom, the reference AV1 codec implementation. The flaw is in the AV1 encoder's Look-Ahead Processing (LAP) mode. The CVSS score for this vulnerability is 7.6, indicating a high severity. Defenders should verify the official CVE record and NVD details for CVE-2026-56208.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-56208 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-56208

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-56208 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-56208

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.