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CVE-2026-6653

Xmlsoft Libxml2 XML external entity (XXE)

9.8 CRITICALPublic exploitEPSS 0.36%
  1. Published22 Jun 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Xmlsoft Libxml2≥ 2.9.11 ≤ 2.11.0

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

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Frequently asked

Is CVE-2026-6653 being actively exploited?

CVE-2026-6653 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.36%.

How severe is CVE-2026-6653?

CVE-2026-6653 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.36% probability of exploitation.

Which products are affected by CVE-2026-6653?

Affected products include Xmlsoft Libxml2.

How do I fix CVE-2026-6653?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-6653 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.