CVE-2026-58049
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 · uneditedFFmpeg's RASC video decoder (decode_dlta in libavcodec/rasc.c) performs 32-bit reads and writes at the row cursor before the NEXT_LINE row-boundary check and validates the DLTA region in pixel rather than byte units, so a DLTA run on a PAL8 frame can access several bytes past the row allocation. A crafted media stream using the RASC FourCC, decoded by libavcodec, triggers a bitstream-controlled out-of-bounds heap write and adjacent out-of-bounds read, leading to memory corruption.
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 confidenceHeap buffer overflow vulnerability in FFmpeg's RASC video decoder where decode_dlta performs 32-bit read/write operations at the row cursor before validating row boundaries, and validates DLTA regions in pixel units instead of bytes, allowing a crafted RASC stream to trigger out-of-bounds heap writes and adjacent reads leading to memory corruption.
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
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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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Confirm FFmpeg is installedRun `ffmpeg -version` to display the installed FFmpeg version and build informationAffected if FFmpeg is present and the version is prior to the patched release containing the RASC decoder fixes
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Verify RASC decoder is availableRun `ffmpeg -decoders 2>/dev/null | grep -i rasc` or `ffprobe -decoders 2>/dev/null | grep -i rasc` to list decoders and check if the RASC FourCC decoder is compiled into the binaryAffected if The RASC decoder appears in the available decoders list, indicating the vulnerable code path could be invoked
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Identify active RASC stream processingInspect any video files or streams for RASC FourCC markers by examining file headers: use a hex viewer or `ffprobe -v trace <file> 2>&1` to look for 'RASC' FourCC code in the video stream metadataAffected if A file or stream with RASC FourCC is being processed or exists in the environment, enabling the decoder to parse the crafted input
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Check for memory corruption indicatorsIf RASC decoding has occurred, review system logs, crash dumps, or application logs for heap corruption errors, segmentation faults, or memory access violations that reference libavcodec/rasc.cAffected if Heap-related crashes or memory corruption events are logged in conjunction with RASC decoder usage
A user is affected if FFmpeg with a vulnerable version is installed, the RASC decoder is compiled in, and RASC-encoded content is being processed or stored in the environment.
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 dataUpgrade to a patched version of FFmpeg that fixes the boundary checking in libavcodec/rasc.c; until then, avoid processing untrusted media files using the RASC FourCC codec.
- Consultation3.0 h
- Implementation6.0 h
- Testing6.0 h
- Review / QA3.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-58049 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
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-2026-58049 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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