CVE-2020-20446Network attack vector

Denial of service via AAC divide-by-zero

Published May 25, 2021 · Updated Aug 4, 2024

Divide-by-zero in FFmpeg 4.2 allows remote attackers to cause a denial of service through crafted AAC or LPC codec input. The libavcodec/aacpsy.c path divides a codec value by zero during AAC psychoacoustic processing. Remote malicious input can interrupt service, while published scoring indicates no confidentiality or integrity impact.

CVSS severity6.5
Medium
EPSS probability1.73%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Divide-by-zero in FFmpeg 4.2 allows remote attackers to cause a denial of service through crafted AAC or LPC codec input. The libavcodec/aacpsy.c path divides a codec value by zero during AAC psychoacoustic processing. Remote malicious input can interrupt service, while published scoring indicates no confidentiality or integrity impact.

The record

CVE
CVE-2020-20446
Published
May 25, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-369, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 25, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.0NVDAV:N/AC:L/Au:S/C:N/I:N/A:P
6.5NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-369Divide By Zero
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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