CVE-2026-6653

Home/CVE/Use After Free in libxml2's xmlParseInternalSubset from GNOME libxml2 version 2.9.11 to 2.11.0 allows a remote attacker

CVE

↯ PDF report

Use After Free in libxml2's xmlParseInternalSubset from GNOME libxml2 version 2.9.11 to 2.11.0 allows a remote attacker

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.

Monitor

⚠ NVD has not scored this CVE yet - manual triage required (common for recent CVEs)

No Sigma yet — build one → YARA rules0

Look this up elsewhere - one-click external pivots

NVD CVE.org CISA Exploit-DB GitHub PoC VulnCheck KEV GreyNoise

▸ How to read a CVE - triage first, then detect and patch

This page is every public fact about CVE-2026-6653, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.

Triage: should I act now? Four signals, and they are not interchangeable:

CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.

How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.

Then what - two workflows:

Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.

Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).

▣

Severity & exploitation scoring

EPSS exploitation probability

n/a

No EPSS score in our data for this CVE. EPSS is published daily for scored CVEs - a very new, reserved, or rejected CVE may not have one yet.

CVSS metric silhouette

No structured CVSS vector for this CVE. Older entries often have only a numeric base score - the metric breakdown radar requires a full AV:_/AC:_/... vector string published by NVD.

SSVC triage · cisa-vulnrichment

Exploitation

none

Automatable

Tech impact

partial

Attack path

Full kill chain

→

◆

ATT&CK techniques

Techniques this CVE enables. Pills with a solid outline are high confidence - named directly in ATT&CK or Nuclei, or human-curated by CTID; the rest are inferred from the weakness type using MITRE's CVE Mapping Methodology and the CWE → CAPEC chain. Broad, generic-weakness guesses are filtered out. A small N× marks a technique that N independent sources agree on.

T1059 · Command and Scripting Interpreter T1499 · Endpoint Denial of Service

▤ Build a SIEM detection for these techniques

▤

CAPEC attack patterns

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-221 · Data Serialization External Entities Blowup

⬡

Weakness Classification

CWE-416Use After Free

CWE-611Improper Restriction of XML External Entity Reference

▤

Related CVEs

CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.

CVE-2006-4434 Use-after-free vulnerability in Sendmail before 8.13.8 allows remote attackers t... same CWE-416 HIGH CVE-2006-4997 The clip_mkip function in net/atm/clip.c of the ATM subsystem in Linux kernel al... same CWE-416 HIGH CVE-2007-3929 Use-after-free vulnerability in the BitTorrent support in Opera before 9.22 allo... same CWE-416 CVE-2008-0077 Use-after-free vulnerability in Microsoft Internet Explorer 6 SP1, 6 SP2, and an... same CWE-416 HIGH CVE-2005-1306 The Adobe Reader control in Adobe Reader and Acrobat 7.0 and 7.0.1 allows remote... 1 same CWE-611 HIGH CVE-2009-1699 The XSL stylesheet implementation in WebKit in Apple Safari before 4.0, iPhone O... 1 same CWE-611 HIGH CVE-2010-3322 The XML parser in Splunk 4.0.0 through 4.1.4 allows remote authenticated users t... same CWE-611 HIGH CVE-2010-2245 XML External Entity (XXE) vulnerability in Apache Wink 1.1.1 and earlier allows ... same CWE-611 HIGH

🔗

References & Sources

Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.

https://bugs.launchpad.net/ubuntu/+source/libxml2/+bug/2141260

https://gitlab.gnome.org/GNOME/libxml2/-/work_items/1058