CVE-2020-20453Network attack vector

Service crash via zero AAC encoding lambda

Published May 25, 2021 · Updated Aug 4, 2024

Divide by zero in FFmpeg 4.2 AAC encoding allows remote authenticated users to crash the processing service via crafted media. The aac_encode_frame routine permits its rate-control lambda to become zero, and downstream AAC coding uses that value as a divisor. Reachability requires an authenticated network path that submits media for AAC encoding; the bounded consequence is termination of the FFmpeg process.

CVSS severity6.5
Medium
EPSS probability1.78%
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 AAC encoding allows remote authenticated users to crash the processing service via crafted media. The aac_encode_frame routine permits its rate-control lambda to become zero, and downstream AAC coding uses that value as a divisor. Reachability requires an authenticated network path that submits media for AAC encoding; the bounded consequence is termination of the FFmpeg process.

The record

CVE
CVE-2020-20453
Published
May 25, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-369, T1499.004
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

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

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
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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