Application crash via unchecked NHML bit width
Published Mar 20, 2026 · Updated Mar 20, 2026
Heap-based buffer overflow in GPAC MP4Box before commit 86b0e36 allows attackers to crash the application through a crafted NHML file. gf_xml_parse_bit_sequence_bs accepts a BS bits attribute above 64, then uses that width in bitstream writes that exceed the allocated heap buffer. Exploitation requires a user to open the malicious file; the demonstrated consequence is an MP4Box crash, while code execution remains unproven.
Summary
What happened
Heap-based buffer overflow in GPAC MP4Box before commit 86b0e36 allows attackers to crash the application through a crafted NHML file. gf_xml_parse_bit_sequence_bs accepts a BS bits attribute above 64, then uses that width in bitstream writes that exceed the allocated heap buffer. Exploitation requires a user to open the malicious file; the demonstrated consequence is an MP4Box crash, while code execution remains unproven.
The record
- CVE
- CVE-2026-33144
- Published
- Mar 20, 2026
- Updated
- Mar 20, 2026
- Vendor
- GPAC Project
- Product
- GPAC
- Classifications
- CWE-787, T1204.002
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 20, 2026CVE publishedPublication date reported by the CVE source.
- Mar 20, 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?
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- Affected versionversion=< 86b0e36ea4c71402fbdaf7e13d73ba8841003e72
What conditions does exploitation require?
What is affected?
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.
Public exploit references
- fuzz_dims.nhml proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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