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CVE-2020-20446· NVD / CVE Program· CNA mitre

FFmpeg 4.2 is affected by a Divide By Zero issue via libavcodec/aacpsy.c, which allows a remote malicious user to cause a Denial of Service.

MediumCVSS 6.5 · v3.1—No exploit Fix available
Published
May 25, 2021
Updated
Jun 16, 2026
EPSS
1.7% · 77th percentile
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Report tools

JSON

Action score

27

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 1.7%

Affected systems

VendorProduct
ffmpegffmpeg
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux10.0
  • debian debian linux11.0
  • debian debian linux9.0
  • ffmpeg ffmpeg4.2

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:10ffmpegbefore 7:4.1.8-0+deb10u17:4.1.8-0+deb10u1
Debian:11ffmpegbefore 7:4.3.3-0+deb11u17:4.3.3-0+deb11u1
Debian:12ffmpegbefore 7:4.4.1-17:4.4.1-1
Debian:9ffmpegbefore 7:3.2.16-1+deb9u17:3.2.16-1+deb9u1

Other highest-scoring records for the same primary product.

  • CVE-2009-4637FFmpeg 0.5 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via unknown vectors that trigger
    45Plan
  • CVE-2016-10190Heap-based buffer overflow in libavformat/http.c in FFmpeg before 2.8.10, 3.0.x before 3.0.5, 3.1.x before 3.1.6, and 3.2.x before 3.2.2 all
    42Plan
  • CVE-2009-4634Multiple integer underflows in FFmpeg 0.5 allow remote attackers to cause a denial of service and possibly execute arbitrary code via a craf
    42Plan
  • CVE-2009-4633vorbis_dec.c in FFmpeg 0.5 uses an assignment operator when a comparison operator was intended, which might allow remote attackers to cause
    42Plan
  • CVE-2016-10192Heap-based buffer overflow in ffserver.c in FFmpeg before 2.8.10, 3.0.x before 3.0.5, 3.1.x before 3.1.6, and 3.2.x before 3.2.2 allows remo
    41Plan
  • CVE-2016-10191Heap-based buffer overflow in libavformat/rtmppkt.c in FFmpeg before 2.8.10, 3.0.x before 3.0.5, 3.1.x before 3.1.6, and 3.2.x before 3.2.2
    41Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:ffmpeg7:4.4.1-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-369 · Divide By Zero

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Change log

  1. Fix✗ → ✓

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References

All records