CVE-2026-12706
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA use-after-free vulnerability was found in FFmpeg's RASC video decoder. The decode_move() function initializes a read pointer into a decompressed buffer, but a subsequent reallocation of that same buffer during move-table processing leaves the pointer dangling. An attacker could exploit this by providing a specially crafted AVI file containing a malicious RASC video stream. When a user opens or plays the file, the decoder reads from freed heap memory, which could lead to a denial of service (crash).
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA use-after-free vulnerability exists in FFmpeg's RASC video decoder where the decode_move() function maintains a read pointer into a decompressed buffer. During move-table processing, the buffer gets reallocated but the old pointer is not updated, leaving it dangling. Opening a specially crafted AVI file with a malicious RASC stream causes the decoder to read from freed heap memory, triggering a crash.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed FFmpeg versionRun 'ffmpeg -version' or 'ffprobe -version' to display the version string. Compare the version number to any recent FFmpeg releases.Affected if The installed version predates the security patch for this vulnerability and the RASC decoder is in use.
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Confirm RASC decoder is availableRun 'ffmpeg -decoders 2>/dev/null | grep -i rasc' or 'ffprobe -codecs 2>/dev/null | grep -i rasc' to list decoders and check if RASC is present.Affected if The RASC decoder appears in the available decoder list.
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Verify RASC is enabled in the current buildRun 'ffmpeg -buildconf 2>/dev/null | grep -i rasc' or check ffmpeg configuration for --enable-decoder=rasc or similar flags.Affected if RASC decoder support is compiled into the FFmpeg binary.
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Identify processes handling AVI filesUse system tools (like 'ps aux' or process monitors) to find running ffmpeg/ffprobe processes actively processing AVI files. Check with 'lsof' on AVI file handles.Affected if FFmpeg is actively decoding AVI files, as the vulnerability triggers during RASC stream processing in AVI containers.
If FFmpeg with a vulnerable version is installed, the RASC decoder is enabled, and the system processes untrusted AVI files containing RASC streams, the environment is affected by this use-after-free vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpdate FFmpeg to the latest version containing the security patch, or temporarily disable the RASC decoder if updates are unavailable. Sanitize or reject untrusted AVI files before processing.
- Consultation3.0 h
- Implementation6.0 h
- Testing5.0 h
- Review / QA3.0 h
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-12706 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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