What is CVE-2026-21531?

CVE-2026-21531 is a critical-severity vulnerability in Microsoft Azure Ai Language Authoring, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-02-10.

How severe is CVE-2026-21531?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Deserialization in Microsoft Azure Ai Language Authoring

CVE-2026-21531

Deserialization of untrusted data in Azure SDK allows an unauthorized attacker to execute code over a network.

Vulnerability class: Insecure Deserialization

EPSS: 0.023 (81.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Microsoft Azure Ai Language Authoring — versions 1.0.0
Microsoft Azure_conversation_authoring_client_library — versions 1.0.0

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

secure@microsoft.com (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-21531?: CVE-2026-21531 is a critical-severity vulnerability in Microsoft Azure Ai Language Authoring, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-02-10.
How severe is CVE-2026-21531?: Critical severity. CVSS v3 base score is 9.8 out of 10.