How severe is CVE-2026-6653?

CVE-2026-6653 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-6653 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-6653?

CVE-2026-6653 affects Xmlsoft Libxml2. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-6653?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-6653 have an EU (EUVD) identifier?

Yes. CVE-2026-6653 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38232.

When was CVE-2026-6653 published?

CVE-2026-6653 was published on 2026-06-22 and last updated on 2026-07-14.

CVE-2026-6653

CVE-2026-6653 is a critical-severity vulnerability in Xmlsoft Libxml2 with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 7.0
EPSS exploit prediction: 0% (27th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-38232
Weakness: CWE-416
Affected product: Xmlsoft Libxml2
Published: 2026-06-22
Last modified: 2026-07-14

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.

Frequently asked questions

What is CVE-2026-6653?: 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.
How severe is CVE-2026-6653?: CVE-2026-6653 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-6653 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-6653?: CVE-2026-6653 affects Xmlsoft Libxml2. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-6653?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-6653 have an EU (EUVD) identifier?: Yes. CVE-2026-6653 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38232.
When was CVE-2026-6653 published?: CVE-2026-6653 was published on 2026-06-22 and last updated on 2026-07-14.

References

Affected products (1)

cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*

More vulnerabilities in Xmlsoft Libxml2

CVE-2008-3529 — Critical (CVSS 10.0): Heap-based buffer overflow in the xmlParseAttValueComplex function in parser.c in libxml2 before 2.7.0 allows…
CVE-2004-0989 — Critical (CVSS 10.0): Multiple buffer overflows in libXML 2.6.12 and 2.6.13 (libxml2), and possibly other versions, may allow remote…
CVE-2017-7376 — Critical (CVSS 9.8): Buffer overflow in libxml2 allows remote attackers to execute arbitrary code by leveraging an incorrect limit for port…
CVE-2017-7375 — Critical (CVSS 9.8): A flaw in libxml2 allows remote XML entity inclusion with default parser flags (i.e., when the caller did not request…
CVE-2017-16931 — Critical (CVSS 9.8): parser.c in libxml2 before 2.9.5 mishandles parameter-entity references because the NEXTL macro calls the…
CVE-2016-4658 — Critical (CVSS 9.8): xpointer.c in libxml2 before 2.9.5 (as used in Apple iOS before 10, OS X before 10.12, tvOS before 10, and watchOS…

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