What is CVE-2026-56209?
An arbitrary address write vulnerability was found in libaom, the reference AV1 codec implementation. A missing bounds check in the SVC (Scalable Video Coding) layer ID control function allows an attacker to inject an arbitrary pointer into the cyclic refresh map field via crafted image pixel values. The encoder then writes approximately 1,200 bytes at the attacker-controlled address. This is fully deterministic and does not require a separate information leak. An attacker who can supply frames to a network-facing libaom encoder with SVC enabled could exploit this for denial of service or potential code execution.
The record classifies CVE-2026-56209 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 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:L/PR:N/UI:R/S:U/C:N/I:L/A:H - CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 3.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-06-19
Is CVE-2026-56209 being exploited?
It currently carries a trending score of 30 in the Threadlinqs vulnerability feed.
Affected products and versions
- Red Hat: Enterprise Linux 10, Enterprise Linux 9, Enterprise Linux AI (RHEL AI) 3, Hardened Images
How to fix CVE-2026-56209
No vendor patch reference has been recorded for CVE-2026-56209 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-2026-56209
No threat campaign in the Threadlinqs corpus currently references CVE-2026-56209, 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. Last verified by Threadlinqs on .