What is the CVSS score of CVE-2026-27821?

CVE-2026-27821 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of Gpac are affected by CVE-2026-27821?

GPAC multimedia framework versions up to 26.02.0 contain a critical stack buffer overflow vulnerability that could allow attackers to execute arbitrary code through malicious NHML files.. A patch is available.

Is there a public PoC exploit available for CVE-2026-27821?

Yes, a public proof-of-concept exploit is available for CVE-2026-27821. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2026-27821?

Within 24 hours: Inventory all systems running GPAC up to version 26.02.0 and assess exposure in production environments. Within 7 days: Apply the available vendor patch to all affected systems and validate deployment in non-production environments first. Within 30 days: Complete patch rollout across all production infrastructure and conduct post-remediation security testing.

Gpac CVE-2026-27821

HIGH

Stack-based Buffer Overflow (CWE-121)

2026-02-26 security-advisories@github.com

Buffer Overflow Gpac

7.8

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

7.8 HIGH

AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

PoC Detected

Mar 11, 2026 - 23:23 vuln.today

Public exploit code

Patch released

Mar 11, 2026 - 23:23 nvd

Patch available

CVE Published

Feb 26, 2026 - 00:16 nvd

HIGH 7.8

DescriptionGitHub Advisory

GPAC is an open-source multimedia framework. In versions up to and including 26.02.0, a stack buffer overflow occurs during NHML file parsing in src/filters/dmx_nhml.c. The value of the xmlHeaderEnd XML attribute is copied from att->value into szXmlHeaderEnd[1000] using strcpy() without any length validation. If the input exceeds 1000 bytes, it overwrites beyond the stack buffer boundary. Commit 9bd7137fded2db40de61a2cf3045812c8741ec52 patches the issue.

AnalysisAI

Stack buffer overflow in GPAC's NHML file parser (versions up to 26.02.0) allows local attackers to achieve code execution by crafting malicious XML files with oversized xmlHeaderEnd attributes that bypass length validation. The vulnerability stems from unsafe use of strcpy() in src/filters/dmx_nhml.c and affects systems processing untrusted NHML files. Public exploit code exists for this vulnerability, though a patch is available.

Technical ContextAI

Classified as CWE-121 (Stack-based Buffer Overflow). Affects Gpac. GPAC is an open-source multimedia framework. In versions up to and including 26.02.0, a stack buffer overflow occurs during NHML file parsing in src/filters/dmx_nhml.c. The value of the xmlHeaderEnd XML attribute is copied from att->value into szXmlHeaderEnd[1000] using strcpy() without any length validation. If the input exceeds 1000 bytes, it overwrites beyond the stack buffer boundary. Commit 9bd7137fded2db40de61a2cf3045812c8741ec52 patches the issue.