Stack Overflow in libxml2 xmlBuildQName (CVE-2025-6021)
CVE-2025-6021 Published on June 12, 2025

Libxml2: integer overflow in xmlbuildqname() leads to stack buffer overflow in libxml2
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.

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Vulnerability Analysis

CVE-2025-6021 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. An automatable proof of concept (POC) exploit exists. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public.

Weakness Type

What is a Memory Corruption Vulnerability?

The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.

CVE-2025-6021 has been classified to as a Memory Corruption vulnerability or weakness.


Products Associated with CVE-2025-6021

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2025-6021 are published in these products:

Enterpriselinux 10 0
 
Rhelels 7
 
Enterpriselinux 8
 
Rhelaus 8 2
 
Rheleuslonglife 8 4
 
Rhelaus 8 4
 
Rheltus 8 6
 
Rhelaus 8 6
 
Rhele4s 8 6
 
Rhele4s 8 8
 
Rheltus 8 8
 
Enterpriselinux 9
 
Rhele4s 9 0
 
Rhele4s 9 2
 
Rheleus 9 4
 
Openshift 4 12
 
Openshift 4 14
 
Openshift 4 15
 
Openshift 4 16
 
Openshift 4 17
 
Openshift 4 18
 
Discovery 2
 
Insightsproxy 1 5
 
Enterpriselinux 6
 
Jbosscoreservices 1
 
Red Hat Enterprise Linux (RHEL)
 
Red Hat Rhel Els
 
Red Hat Rhel Aus
 
Red Hat Rhel Eus Long Life
 
Red Hat Rhel Tus
 
Red Hat Rhel E4s
 
Red Hat Rhel Eus
 
Red Hat Openshift
 
Red Hat Discovery
 
Red Hat Insights Proxy
 
Red Hat Jboss Core Services
 
Red Hat Rhivos
 
Oracle
 
Red Hat Http Server
 

Vulnerable Packages

The following package name and versions may be associated with CVE-2025-6021

Package Manager Vulnerable Package Versions Fixed In
rubygems nokogiri < 1.18.9 1.18.9

Exploit Probability

EPSS
0.76%
Percentile
73.28%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.