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Ubuntu LinuxOperating system · Canonical

CVE-2020-12284

CRITICAL · 9.8 CVSS v3.1 Published 2020-04-28
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click Patch available

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 · unedited
cbs_jpeg_split_fragment in libavcodec/cbs_jpeg.c in FFmpeg 4.1 and 4.2.2 has a heap-based buffer overflow during JPEG_MARKER_SOS handling because of a missing length check.

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
How this class of weakness works · CWE-787

The program writes past the bounds of a buffer, overwriting adjacent memory an attacker can turn to their advantage. Crafted input can overwrite control data and redirect execution. Remediation is validating every index and length before a write, plus modern memory-safety mitigations.

General guidance for the out-of-bounds write class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Ubuntu LinuxOperating system
Affected:= 16.04= 18.04= 20.04
Debian LinuxOperating system
Affected:= 10.0
FfmpegApplication
Affected:= 4.1= 4.2.2

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix High confidence

FFmpeg 4.3 or later (e.g., 4.3.1, 4.4)

  1. 1. Identify the FFmpeg package version currently installed: `ffmpeg -version` or `dpkg -l | grep ffmpeg`
  2. 2. For Ubuntu systems: Run `sudo apt update` then `sudo apt install ffmpeg` to install the latest available version with security patches
  3. 3. For Debian systems: Run `sudo apt update` then `sudo apt install ffmpeg` or check for security updates via `sudo apt-get update && sudo apt-get install -y libavcodec-extra`
  4. 4. Verify the fix was applied by checking the version: `ffmpeg -version`. Ensure version is 4.3 or later which contains the commit 1812352d
  5. 5. Alternatively, rebuild FFmpeg from source after applying vendor patch commit 1812352d767ccf5431aa440123e2e260a4db2726
Caveat Minor: Some encoding/decoding options may have changed between 4.2.x and 4.3+. Review ffmpeg -help output for any deprecated flags.

Generated from the published advisory — verify against the referenced sources before acting.

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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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-12284 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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