What is CVE-2026-56407?

CVE-2026-56407 is a security advisory published by Microsoft Security Response Center (MSRC) with Medium severity. libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity textLen.

Which CVE IDs does CVE-2026-56407 cover?

CVE-2026-56407 covers the following CVE IDs: CVE-2026-56407. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of CVE-2026-56407?

CVE-2026-56407 has a CVSS v3 base score of 6.9, published by Microsoft Security Response Center (MSRC).

Which products are affected by CVE-2026-56407?

CVE-2026-56407 affects 3 products, including: azl3 cmake 3.30.3-13 on Azure Linux 3.0; azl3 expat 2.6.4-6 on Azure Linux 3.0; azl3 python3 3.12.9-11 on Azure Linux 3.0.

CVE-2026-56407MediumCVSS 6.9

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

Vendor

Microsoft Security Response Center (MSRC)

Published

June 30, 2026

Last Modified

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🔗 CVE IDs covered (1)

CVE-2026-56407 →

🎯 Affected products3

azl3 cmake 3.30.3-13 on Azure Linux 3.0
azl3 expat 2.6.4-6 on Azure Linux 3.0
azl3 python3 3.12.9-11 on Azure Linux 3.0

✅ Remediation

KBCBL-Mariner Releases (Security Update) — fixed build 2.8.2-1

🔗 References (2)

advisoryhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56407
referencehttps://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade