Critical CVSS 9.1 EPSS 0.05091 2026-05 archive

Executive Summary

Incorrect implementation of authentication algorithm in Microsoft SSO Plugin for Jira & Confluence allows an unauthorized attacker to elevate privileges over a network.

Overview

9.1
CVSS CRITICAL
Critical
MS Severity
Not Exploited
MS Exploit Status
More Likely
MS Exploit Likelihood
Category Elevation of Privilege
Released May 12 2026
Last Updated May 12 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.05091 — 0.91256 percentile
NVD CVSS 9.1 CRITICAL — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
None
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.9

EPSS Score

0.05091
probability of exploitation in the next 30 days
0.91256 percentile - updated 2026-06-21
View on FIRST.org

Affected Products

1 affected product
Product KB Article Severity Impact Restart Required
Microsoft Confluence SAML SSO plugin Release Notes (Security Update) Critical Elevation of Privilege No

Patches

1 patch
Article Type Restart
Release Notes Security Update No

Known Exploits

Acknowledgments

Robert Fitzpatrick with Microsoft