VDB-340818 · CVE-2026-20929 · GCVE-0-2026-20929

Microsoft Windows up to Server 2022 23H2 HTTP.sys access control

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, which was classified as critical, was found in Microsoft Windows. Impacted is an unknown function in the library HTTP.sys. The manipulation results in access control. This vulnerability was named CVE-2026-20929. The attack may be performed from remote. There is no available exploit. A patch should be applied to remediate this issue.

Detailsinfo

A vulnerability was found in Microsoft Windows. It has been classified as critical. Affected is some unknown functionality in the library HTTP.sys. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Improper access control in Windows HTTP.sys allows an authorized attacker to elevate privileges over a network.

The weakness was presented 01/13/2026 as confirmed security update guide (Website). The advisory is available at msrc.microsoft.com. This vulnerability is traded as CVE-2026-20929. The exploitability is told to be difficult. It is possible to launch the attack remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 01/17/2026). This vulnerability is assigned to T1068 by the MITRE ATT&CK project.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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: 7.5
VulDB Meta Temp Score: 6.8

VulDB Base Score: 7.5
VulDB Temp Score: 6.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 7.5
Vendor Vector (Microsoft): 🔒

CNA Base Score: 7.5
CNA Vector (Microsoft): 🔒

CVSSv2info

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

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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: Patch
Status: 🔍

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

Timelineinfo

01/13/2026 VulDB entry created
01/13/2026 +0 days Advisory disclosed
01/13/2026 +0 days Countermeasure disclosed
01/17/2026 +3 days VulDB entry last update