CVE-2020-20902Network attack vector

Information disclosure via out-of-bounds G.729 signal pointer

Published Sep 20, 2021 · Updated Aug 4, 2024

Out-of-bounds read in FFmpeg 4.2.1 allows remote attackers to disclose process memory through crafted G.729 audio requiring user interaction. The long_term_filter function in libavcodec/g729postfilter.c evaluates pointer subtraction before addition, transiently forming an address 49 int16_t elements before the signal buffer during the R'(0) denominator calculation. Processing attacker-controlled G.729 media is required; the reported consequence is memory disclosure, with no integrity or availability impact.

CVSS severity6.5
Medium
EPSS probability1.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in FFmpeg 4.2.1 allows remote attackers to disclose process memory through crafted G.729 audio requiring user interaction. The long_term_filter function in libavcodec/g729postfilter.c evaluates pointer subtraction before addition, transiently forming an address 49 int16_t elements before the signal buffer during the R'(0) denominator calculation. Processing attacker-controlled G.729 media is required; the reported consequence is memory disclosure, with no integrity or availability impact.

The record

CVE
CVE-2020-20902
Published
Sep 20, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 20, 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

4.3NVDAV:N/AC:M/Au:N/C:P/I:N/A:N
6.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read

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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