HIGH

CVE-2025-6021

CVSS v3

7.5

HIGH

EPSS Score

1.4 %

exploit probability, as of 2026-10-19

CISA KEV

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

javaBitnamiall versions · fixed in 1.8.0and 2 other packages
libxml2AlmaLinux:10all versions · fixed in 2.12.5-7.el10_0and 3 other packages
libxml2AlmaLinux:9all versions · fixed in 2.9.13-10.el9_6and 2 other packages
libxml2AlmaLinux:8all versions · fixed in 2.9.7-21.el8_10.1and 2 other packages

Vendor advisories

CVE-2025-6021 Red Hat Product Security540 products fixed · 5 known affected
libxml2: Integer Overflow in xmlBuildQName() Leads to Stack Buffer Overflow in libxml2
libxml2 as a component of Red Hat Enterprise Linux 6 · libxml2-devel as a component of Red Hat Enterprise Linux 6 · libxml2-python as a component of Red Hat Enterprise Linux 6
ICSA-26-134-10 CISA1 known affected
Siemens SIMATIC
SIMATIC CN 4100
SSA-032379 Siemens ProductCERT1 known affected
SSA-032379: Multiple Vulnerabilities in SIMATIC CN 4100 Before V5.0
SIMATIC CN 4100
RHSA-2026:7519 Red Hat Product Security11 products fixed
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
RHSA-2025:19020 Red Hat Product Security1 product fixed
Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP2 security update
RHSA-2025:15672 Red Hat Product Security1 product fixed
Red Hat Security Advisory: OpenShift Container Platform 4.13.60 bug fix and security update

19 more advisories

Full record on NVD

Description

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 input.

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2025-06-12
Last Modified: 2026-05-12

Frequently asked questions

What is CVE-2025-6021?

Is CVE-2025-6021 actively exploited?

Active exploitation of CVE-2025-6021 has not been confirmed. Its EPSS score was 1.4% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2025-6021?

CVE-2025-6021 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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