How severe is CVE-2026-27821?

CVE-2026-27821 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-27821 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-27821?

CVE-2026-27821 affects Gpac. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27821?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-27821 have an EU (EUVD) identifier?

Yes. CVE-2026-27821 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8784.

When was CVE-2026-27821 published?

CVE-2026-27821 was published on 2026-02-26 and last updated on 2026-06-17.

CVE-2026-27821

CVE-2026-27821 is a high-severity vulnerability in Gpac with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-121.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v4: 7.7
EPSS exploit prediction: 0% (19th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-8784
Weakness: CWE-121
Affected product: Gpac
Published: 2026-02-26
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-27821?: 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.
How severe is CVE-2026-27821?: CVE-2026-27821 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-27821 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-27821?: CVE-2026-27821 affects Gpac. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27821?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-27821 have an EU (EUVD) identifier?: Yes. CVE-2026-27821 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8784.
When was CVE-2026-27821 published?: CVE-2026-27821 was published on 2026-02-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:gpac:gpac:*:*:*:*:*:*:*:*

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