CVE-2026-75141

Heap overflow via wrapped hvcC count

Published Aug 19, 2026 · Updated Aug 21, 2026

Heap buffer overflow in FFmpeg before commit acf5d7c allows attackers to corrupt heap memory via a crafted HEVC file during muxing. The hvcC box writer stores the number of NAL units of a single type in a count field that can overflow; once that wrapped count is used while emitting the HEVC configuration record, later writes run past the allocated heap buffer. Reachability requires HEVC muxing of attacker-supplied content, limiting exposure to workflows that ingest untrusted files for local conversion or packaging, with crash or potential code-execution impact in the FFmpeg process.

CVSS severity8.5
High
EPSS probability0.14%
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 FFmpeg before commit acf5d7c allows attackers to corrupt heap memory via a crafted HEVC file during muxing. The hvcC box writer stores the number of NAL units of a single type in a count field that can overflow; once that wrapped count is used while emitting the HEVC configuration record, later writes run past the allocated heap buffer. Reachability requires HEVC muxing of attacker-supplied content, limiting exposure to workflows that ingest untrusted files for local conversion or packaging, with crash or potential code-execution impact in the FFmpeg process.

The record

CVE
CVE-2026-75141
Published
Aug 19, 2026
Updated
Aug 21, 2026
Vendor
FFmpeg
Product
FFmpeg
Classifications
CWE-122, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <acf5d7cdc1f9ae8752c23e1ea8d7f355ed780781

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

FFmpeg · FFmpegversion=0 <acf5d7cdc1f9ae8752c23e1ea8d7f355ed780781

Published CVSS scores

7.8VulnCheckCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.5VulnCheckCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA: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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1203Exploitation for Client Execution

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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