VDB-378844 · CVE-2026-54121 · GCVE-0-2026-54121

Microsoft Windows up to Server 2025 Active Directory Certificate Services Certighost improper authorization

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.9	$0-$5k	0.00

Summaryinfo

A vulnerability was found in Microsoft Windows up to Server 2025 and classified as very critical. This issue affects some unknown processing of the component Active Directory Certificate Services. Executing a manipulation can lead to improper authorization. The identification of this vulnerability is CVE-2026-54121. The attack may be launched remotely. Furthermore, there is an exploit available. It is advisable to implement a patch to correct this issue.

Detailsinfo

A vulnerability was found in Microsoft Windows up to Server 2025. It has been declared as very critical. This vulnerability affects an unknown code of the component Active Directory Certificate Services. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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

The advisory is shared for download at msrc.microsoft.com. This vulnerability was named CVE-2026-54121 since 06/11/2026. The exploitation appears to be easy. The attack can be initiated remotely. Technical details are unknown but a public exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/28/2026). The MITRE ATT&CK project declares the attack technique as T1548.002.

It is possible to download the exploit at github.com. It is declared as proof-of-concept.

Applying a patch is able to eliminate this problem.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Operating System

Vendor

Microsoft

Name

Windows

Version

License

commercial

Website

Vendor: https://www.microsoft.com/
Product: https://www.microsoft.com/en-us/windows

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 8.9

VulDB Base Score: 9.9
VulDB Temp Score: 8.9
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper authorization
CWE: CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Timelineinfo

06/11/2026 CVE reserved
07/14/2026 +33 days VulDB entry created
07/15/2026 +0 days Advisory disclosed
07/28/2026 +13 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-54121 (🔒)
GCVE (CVE): GCVE-0-2026-54121
GCVE (VulDB): GCVE-100-378844
scip Labs: https://www.scip.ch/en/?labs.20161215

Entryinfo

Created: 07/15/2026 00:07
Updated: 07/28/2026 16:06
Changes: 07/15/2026 00:07 (53), 07/28/2026 16:05 (10), 07/28/2026 16:06 (4)
Complete: 🔍
Cache ID: 216::103