Microsoft Windows up to Server 2025 Remote Desktop Licensing Service missing authentication

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.
6.8	$5k-$25k	0.00

Summaryinfo

A vulnerability described as critical has been identified in Microsoft Windows. This vulnerability affects unknown code of the component Remote Desktop Licensing Service. Such manipulation leads to missing authentication. This vulnerability is traded as CVE-2026-26159. An attack has to be approached locally. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Microsoft Windows and classified as critical. Affected by this issue is an unknown code block of the component Remote Desktop Licensing Service. The manipulation with an unknown input leads to a missing authentication vulnerability. Using CWE to declare the problem leads to CWE-306. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. Impacted is confidentiality, integrity, and availability.

The weakness was shared 04/14/2026 as confirmed security update guide (Website). The advisory is shared for download at msrc.microsoft.com. This vulnerability is handled as CVE-2026-26159. The exploitation is known to be easy. The attack needs to be approached locally. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 05/31/2026).

Upgrading to version 10.0.14393.9060, 10.0.17763.8644, 10.0.19044.7184, 10.0.19045.7184, 10.0.20348.5020, 10.0.22631.6936, 10.0.25398.2274, 10.0.26100.32690, 10.0.26200.8246, 10.0.28000.1836, 6.2.9200.26026 or 6.3.9600.23132 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1730). Once again VulDB remains the best source for vulnerability data.

Affected

• Xerox FreeFlow Print Server

Productinfo

Type

• Operating System

Vendor

• Microsoft

Name

• Windows

Version

• 10 21H2
• 10 1607
• 10 1809
• 11 23H2
• 11 24H2
• 11 25H2
• 11 26H1
• Server 2016
• Server 2019
• Server 2022
• Server 2022 23H2
• Server 2025

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: 7.8
VulDB Meta Temp Score: 6.8

VulDB Base Score: 7.8
VulDB Temp Score: 6.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 7.8
Vendor Vector (Microsoft): 🔒

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: Missing authentication
CWE: CWE-306 / CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Unproven

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: Upgrade
Status: 🔍

Reaction Time: 🔒
0-Day Time: 🔒
Exposure Time: 🔒

Upgrade: Windows 10.0.14393.9060/10.0.17763.8644/10.0.19044.7184/10.0.19045.7184/10.0.20348.5020/10.0.22631.6936/10.0.25398.2274/10.0.26100.32690/10.0.26200.8246/10.0.28000.1836/6.2.9200.26026/6.3.9600.23132

Timelineinfo

04/14/2026 VulDB entry created
04/14/2026 +0 days Advisory disclosed
04/14/2026 +0 days Countermeasure disclosed
05/31/2026 +46 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-26159 (🔒)
GCVE (CVE): GCVE-0-2026-26159
GCVE (VulDB): GCVE-100-357404
CERT Bund: WID-SEC-2026-1730 - Xerox FreeFlow Print Server: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff

scip Labs: https://www.scip.ch/en/?labs.20161215

Entryinfo

Created: 04/14/2026 19:28
Updated: 05/31/2026 14:49
Changes: 04/14/2026 19:28 (38), 04/14/2026 19:31 (32), 05/31/2026 14:49 (7)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

Discussion

Do you know our Splunk app?

Download it now for free!