What is CVE-2026-56403?

CVE-2026-56403 is a security advisory published by Microsoft Security Response Center (MSRC) with Medium severity. libexpat before 2.8.2 has an integer overflow in storeAtts.

Which CVE IDs does CVE-2026-56403 cover?

CVE-2026-56403 covers the following CVE IDs: CVE-2026-56403. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of CVE-2026-56403?

CVE-2026-56403 has a CVSS v3 base score of 6.9, published by Microsoft Security Response Center (MSRC).

CVE-2026-56403MediumCVSS 6.9

libexpat before 2.8.2 has an integer overflow in storeAtts.

Vendor

Microsoft Security Response Center (MSRC)

Published

June 30, 2026

Last Modified

—

🔗 CVE IDs covered (1)

CVE-2026-56403 →