CVE-2020-21066Public exploitNetwork attack vector

Crash via unchecked dec3 substream parsing

Published Aug 13, 2021 · Updated Aug 4, 2024

Heap-buffer overflow in Bento4 1.5.1.0 allows remote attackers to crash mp42aac via a crafted MP4 file containing a malformed dec3 atom. The AP4_Dec3Atom constructor reads payload[3] for a dependent E-AC-3 substream without checking that enough payload bytes remain. A user must cause mp42aac or another Bento4-based parser to process the crafted file; the demonstrated consequence is an application crash.

CVSS severity6.5
Medium
EPSS probability0.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-buffer overflow in Bento4 1.5.1.0 allows remote attackers to crash mp42aac via a crafted MP4 file containing a malformed dec3 atom. The AP4_Dec3Atom constructor reads payload[3] for a dependent E-AC-3 substream without checking that enough payload bytes remain. A user must cause mp42aac or another Bento4-based parser to process the crafted file; the demonstrated consequence is an application crash.

The record

CVE
CVE-2020-21066
Published
Aug 13, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 13, 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 privilegesunauthenticated

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:N/UI:R/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499.004Application or System Exploitation

Public exploit references

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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