CVE-2026-54121: exploitation status and patch state

CVE-2026-54121 · CVSS 8.8 HIGH · patch available

Improper authorization in Active Directory Certificate Services (AD CS) allows an authorized attacker to elevate privileges over a network.

Is CVE-2026-54121 exploited?

• Not in the CISA KEV catalog.
• Public exploit code: none found in monitored sources.

Which products and versions are affected?

No affected package list recorded here yet.

Is there a patch?

• KB5099538
• KB5099540
• KB5099536
• KB5099535
• KB5099445
• KB5099444

What PlainSec published about CVE-2026-54121

• AD CS Trust Check Hands Users Domain Controller Power (2026-07-28)

Primary sources

• NVD record
• Microsoft KB5099538
• Microsoft KB5099540
• Microsoft KB5099536
• Microsoft KB5099535
• Microsoft KB5099445
• Microsoft KB5099444

What this record does not say

• No EPSS score.
• No affected package data.

KEV and EPSS are re-checked daily. Record last updated 2026-08-14.