CVE-2026-6653
libxml2: Use after free in xmlParseInternalSubset via improper entity resolution handling
Description
Use After Free in libxml2's xmlParseInternalSubset from GNOME libxml2 version 2.9.11 to 2.11.0 allows a remote attacker to cause a denial-of-service via maliciously crafted XML input with improper entity resolution handling.
INFO
Published Date :
June 22, 2026, 2:17 p.m.
Last Modified :
July 14, 2026, 4 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 4.0 | HIGH | cc1ad9ee-3454-478d-9317-d3e869d708bc | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update libxml2 to a patched version.
- Ensure proper XML entity resolution handling.
- Validate all XML inputs.
Public PoC/Exploit Available at Github
CVE-2026-6653 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-6653.
| URL | Resource |
|---|---|
| https://bugs.launchpad.net/ubuntu/+source/libxml2/+bug/2141260 | Exploit Issue Tracking Third Party Advisory |
| https://gitlab.gnome.org/GNOME/libxml2/-/work_items/1058 | Exploit Issue Tracking Patch |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-6653 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-6653
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
Shell Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-6653 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-6653 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Added CPE Configuration OR *cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:* versions from (including) 2.9.11 up to (including) 2.11.0 Added Reference Type Canonical Ltd.: https://bugs.launchpad.net/ubuntu/+source/libxml2/+bug/2141260 Types: Exploit, Issue Tracking, Third Party Advisory Added Reference Type Canonical Ltd.: https://gitlab.gnome.org/GNOME/libxml2/-/work_items/1058 Types: Exploit, Issue Tracking, Patch -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 22, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-6653', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-22T15:51:00.508541Z'} -
New CVE Received by [email protected]
Jun. 22, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://gitlab.gnome.org/GNOME/libxml2', 'vendor': 'GNOME', 'product': 'libxml2', 'versions': [{'status': 'affected', 'version': '2.9.11', 'lessThan': '2.11.0', 'versionType': 'semver'}], 'packageName': 'libxml2', 'defaultStatus': 'unaffected'}] Added Description Use After Free in libxml2's xmlParseInternalSubset from GNOME libxml2 version 2.9.11 to 2.11.0 allows a remote attacker to cause a denial-of-service via maliciously crafted XML input with improper entity resolution handling. Added CVSS V4.0 AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-416 Added CWE CWE-611 Added Reference https://bugs.launchpad.net/ubuntu/+source/libxml2/+bug/2141260 Added Reference https://gitlab.gnome.org/GNOME/libxml2/-/work_items/1058