Buffer overflow in Xmlsoft Libxml2

CVE-2025-6021

A flaw was found in libxml2's xmlBuildQName function, where integer overflows in buffer size calculations can lead to a stack-based buffer overflow. This issue can result in memory corruption or a denial of service when processing crafted…

Vulnerability class: Buffer Overflow

EPSS: 0.021 (84.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-6021?
CVE-2025-6021 is a high-severity vulnerability in Xmlsoft Libxml2, classified under Out-of-bounds Write. CVSS score: 7.5/10. Published 2025-06-12.
How severe is CVE-2025-6021?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-6021 known to be exploited?
8 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.