How severe is CVE-2026-56407?

CVE-2026-56407 has a CVSS 3.x base score of 6.9, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.

Is CVE-2026-56407 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-2026-56407?

CVE-2026-56407 affects Libexpat Project Libexpat. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-56407?

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

Does CVE-2026-56407 have an EU (EUVD) identifier?

Yes. CVE-2026-56407 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38184.

When was CVE-2026-56407 published?

CVE-2026-56407 was published on 2026-06-21 and last updated on 2026-06-23.

CVE-2026-56407

CVE-2026-56407 is a medium-severity vulnerability in Libexpat Project Libexpat with a CVSS 3.x base score of 6.9. 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-190.

Key facts

Severity: Medium (CVSS 3.x base score 6.9)
EPSS exploit prediction: 0% (1st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-38184
Weakness: CWE-190
Affected product: Libexpat Project Libexpat
Published: 2026-06-21
Last modified: 2026-06-23

Description

libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity textLen.

Frequently asked questions

What is CVE-2026-56407?: libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity textLen.
How severe is CVE-2026-56407?: CVE-2026-56407 has a CVSS 3.x base score of 6.9, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.
Is CVE-2026-56407 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-2026-56407?: CVE-2026-56407 affects Libexpat Project Libexpat. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-56407?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-56407 have an EU (EUVD) identifier?: Yes. CVE-2026-56407 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38184.
When was CVE-2026-56407 published?: CVE-2026-56407 was published on 2026-06-21 and last updated on 2026-06-23.

References

https://github.com/libexpat/libexpat/pull/1262

Affected products (1)

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

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