What is CVE-2026-21529?

CVE-2026-21529 is a medium-severity vulnerability in Microsoft Azure Hdinsight, classified under Cross-site Scripting. CVSS score: 5.7/10. Published 2026-02-10.

How severe is CVE-2026-21529?

Medium severity. CVSS v3 base score is 5.7 out of 10.

XSS in Microsoft Azure Hdinsight

CVE-2026-21529

Improper neutralization of input during web page generation ('cross-site scripting') in Azure HDInsights allows an authorized attacker to perform spoofing over a network.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-02-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.7 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.007 (51.2th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.007 · change: +0.000

Affected products

Microsoft Azure Hdinsight — versions 1.0
Microsoft Azure Hdinsight

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

Azure HDInsight Spoofing Vulnerability (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-21529?: CVE-2026-21529 is a medium-severity vulnerability in Microsoft Azure Hdinsight, classified under Cross-site Scripting. CVSS score: 5.7/10. Published 2026-02-10.
How severe is CVE-2026-21529?: Medium severity. CVSS v3 base score is 5.7 out of 10.