CVE-2026-65706 FFmpeg vulnerability
FFmpeg versions 3.0 through 8.1.2 contain an out-of-bounds write vulnerability in the vf_swaprect video filter that allows attackers to corrupt heap memory by supplying a crafted NV12 video frame with odd width dimensions. The filter_frame() function reuses a temporary row buffer sized for plane 0's single-byte pixel step across all planes, causing an 18-byte memcpy into a 17-byte heap allocation when processing the two-byte-per-sample interleaved chroma plane of a 17x16 NV12 frame, resulting in heap corruption and process crash with potential for code execution.
Browse Memory Corruption security risksQuick answer
FFmpeg should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- <= 8.1.2
Fixed versions
- a7e38b617b32f996beaa371bbf04b39907d7a527
How to fix it
CVE-2026-65706 affects FFmpeg and involves memory-safety failure. A crafted input may crash the affected process and interrupt service. Prioritize internet-facing, privileged, automation, and production deployments. Upgrade FFmpeg to a7e38b617b32f996beaa371bbf04b39907d7a527 or a later vendor-supported fixed release.
- Inventory every deployment, device, package, plugin, container, build, and environment that uses FFmpeg.
- Compare the installed version with the recorded affected range: <= 8.1.2.
- Upgrade FFmpeg to a7e38b617b32f996beaa371bbf04b39907d7a527 or a later vendor-supported fixed release.
- Until patched, limit untrusted files and peers, apply resource limits, and isolate the affected parser or service.
- Review configuration, roles, tokens, network paths, and exposed endpoints connected to FFmpeg; remove access that is not required.
- Review application, system, proxy, and audit logs for requests and behavior linked to the affected feature and CVE.
- If exploitation is suspected, isolate affected assets, preserve evidence, rotate exposed credentials or keys, restore trusted data, and rebuild compromised systems before returning them to service.
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Verify the fix
- Confirm every affected asset now runs the fixed vendor-supported release or has the documented mitigation for CVE-2026-65706 in place.
- Use a safe regression test to confirm the affected memory-safety failure path no longer produces the vulnerable behavior.
- Confirm temporary access controls, endpoint restrictions, network blocks, and least-privilege settings remain effective after the update.
- Review post-remediation logs and rerun Fixnx plus the relevant package, dependency, firmware, browser, or product-specific security check.
- Document affected assets, versions, changes, validation evidence, reviewed logs, and any credential rotation, cleanup, or replacement completed.
Related categories
Related security risks
More published guidance from the same primary category.
Trusted references
FAQ
What is affected by CVE-2026-65706?
FFmpeg versions listed as affected should be reviewed: <= 8.1.2.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.