What is CVE-2026-56211?
A remote code execution vulnerability was found in libaom, the reference AV1 codec implementation. Insufficient bounds validation in the AV1 encoder's SVC (Scalable Video Coding) layer ID control allows an attacker to supply crafted video frame pixels that overlap with internal encoder layer context structures. In fork-based video processing services, an attacker can use this to hijack the cyclic refresh map pointer, brute-force the process base address via a crash oracle, and redirect control flow to achieve arbitrary command execution. Exploitation requires the target service to use libaom with SVC encoding enabled and accept attacker-supplied video frames.
The record classifies CVE-2026-56211 under weakness class CWE-787. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first, and has high impact on integrity, availability. 4 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 108 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.1 — HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:H - CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 5.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-06-19
Is CVE-2026-56211 being exploited?
Weaponised exploit code for CVE-2026-56211 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 38 in the Threadlinqs vulnerability feed.
- trickest/cve (trickest)
Affected products and versions
- Red Hat: Enterprise Linux 10, Enterprise Linux 9, Enterprise Linux AI (RHEL AI) 3, Hardened Images
How to fix CVE-2026-56211
No vendor patch reference has been recorded for CVE-2026-56211 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-56211
No threat campaign in the Threadlinqs corpus currently references CVE-2026-56211, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on .