CVE-2021-40570Public exploit

Code execution via unchecked H.264 POC length

Published Jan 13, 2022 · Updated Aug 4, 2024

Double free in MP4Box in GPAC 1.0.1 allows local users to crash the process or execute code by opening a crafted H.264 file. The SPS parser leaves an oversized poc_cycle_length intact after detecting that it exceeds the offset_for_ref_frame array, so avc_compute_poc later consumes invalid parser state. Execution requires MP4Box to process attacker-controlled media; observed behavior is a segmentation fault, while the CVE record also attributes code execution and privilege escalation.

CVSS severity7.8
High
EPSS probability1.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double free in MP4Box in GPAC 1.0.1 allows local users to crash the process or execute code by opening a crafted H.264 file. The SPS parser leaves an oversized poc_cycle_length intact after detecting that it exceeds the offset_for_ref_frame array, so avc_compute_poc later consumes invalid parser state. Execution requires MP4Box to process attacker-controlled media; observed behavior is a segmentation fault, while the CVE record also attributes code execution and privilege escalation.

The record

CVE
CVE-2021-40570
Published
Jan 13, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-415, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 13, 2022CVE 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 vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-415Double Free
T1204.002User Execution: Malicious File

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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