What is CVE-2026-21535?

CVE-2026-21535 is a high-severity vulnerability in Microsoft Teams, classified under Improper Access Control. CVSS score: 8.2/10. Published 2026-02-19.

How severe is CVE-2026-21535?

High severity. CVSS v3 base score is 8.2 out of 10.

Vulnerability in Microsoft Teams

CVE-2026-21535

Improper access control in Microsoft Teams allows an unauthorized attacker to disclose information over a network.

Published 2026-02-19 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (50.7th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 50.7% 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: +0.001

Affected products

Weakness classification (CWE)

CWE-284 — Improper Access Control

References

Microsoft Teams Information Disclosure Vulnerability (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-21535?: CVE-2026-21535 is a high-severity vulnerability in Microsoft Teams, classified under Improper Access Control. CVSS score: 8.2/10. Published 2026-02-19.
How severe is CVE-2026-21535?: High severity. CVSS v3 base score is 8.2 out of 10.