CVE-2021-33362

Code execution via unchecked output-layer-set count

Published Sep 13, 2021 · Updated Aug 3, 2024

Stack buffer overflow in MP4Box in GPAC 1.0.1 allows local users to execute arbitrary code or crash the process via a crafted HEVC file. hevc_parse_vps_extension computes num_output_layer_sets from untrusted VPS fields but fails to reject values above MAX_LHVC_LAYERS before accessing layer arrays. A victim must cause MP4Box to parse the file; successful corruption executes code with that process's privileges, while other outcomes crash it.

CVSS severity7.8
High
EPSS probability1.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in MP4Box in GPAC 1.0.1 allows local users to execute arbitrary code or crash the process via a crafted HEVC file. hevc_parse_vps_extension computes num_output_layer_sets from untrusted VPS fields but fails to reject values above MAX_LHVC_LAYERS before accessing layer arrays. A victim must cause MP4Box to parse the file; successful corruption executes code with that process's privileges, while other outcomes crash it.

The record

CVE
CVE-2021-33362
Published
Sep 13, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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

7.8Canonical Ubuntu SecurityCVSS: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
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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-787Out-of-bounds Write
T1204.002Malicious File

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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