How severe is CVE-2026-56131?

CVE-2026-56131 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-56131 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-56131?

CVE-2026-56131 affects Libexpat Project Libexpat. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-56131?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-56131 have an EU (EUVD) identifier?

Yes. CVE-2026-56131 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37976.

When was CVE-2026-56131 published?

CVE-2026-56131 was published on 2026-06-19 and last updated on 2026-06-23.

CVE-2026-56131

CVE-2026-56131 is a medium-severity vulnerability in Libexpat Project Libexpat with a CVSS 3.x base score of 4.9. 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: Medium (CVSS 3.x base score 4.9)
EPSS exploit prediction: 0% (1st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-37976
Weakness: CWE-416
Affected product: Libexpat Project Libexpat
Published: 2026-06-19
Last modified: 2026-06-23

Description

libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_ResumeParser from within handlers in cases of a policy violation. Thus, a use-after-free can occur (similar to the CVE-2026-50219 situation).

Frequently asked questions

What is CVE-2026-56131?: libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_ResumeParser from within handlers in cases of a policy violation. Thus, a use-after-free can occur (similar to the CVE-2026-50219 situation).
How severe is CVE-2026-56131?: CVE-2026-56131 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-56131 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-56131?: CVE-2026-56131 affects Libexpat Project Libexpat. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-56131?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-56131 have an EU (EUVD) identifier?: Yes. CVE-2026-56131 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37976.
When was CVE-2026-56131 published?: CVE-2026-56131 was published on 2026-06-19 and last updated on 2026-06-23.

References

https://github.com/libexpat/libexpat/pull/1267

Affected products (1)

cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*

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