VDB-357535 · CVE-2026-33099 · WID-SEC-2026-1730

Microsoft Windows up to Server 2022 23H2 Ancillary Function Driver for WinSock use after free

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.
6.1	$5k-$25k	0.00

Summaryinfo

A vulnerability has been found in Microsoft Windows and classified as critical. This affects an unknown part of the component Ancillary Function Driver for WinSock. This manipulation causes use after free. This vulnerability is registered as CVE-2026-33099. The attack needs to be launched locally. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical was found in Microsoft Windows. Affected by this vulnerability is an unknown part of the component Ancillary Function Driver for WinSock. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was published 04/14/2026 as confirmed security update guide (Website). It is possible to read the advisory at msrc.microsoft.com. This vulnerability is known as CVE-2026-33099. The exploitation appears to be difficult. Attacking locally is a requirement. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 06/01/2026).

Upgrading to version 6.2.9200.26026, 6.3.9600.23132, 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 or 10.0.26200.8246 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). Be aware that VulDB is the high quality source for vulnerability data.

Affected

Xerox FreeFlow Print Server

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: 7.0
VulDB Meta Temp Score: 6.1

VulDB Base Score: 7.0
VulDB Temp Score: 6.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 7.0
Vendor Vector (Microsoft): 🔒

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
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 6.2.9200.26026/6.3.9600.23132/10.0.14393.9060/10.0.17763.8644/10.0.19044.7184/10.0.19045.7184/10.0.20348.5020/10.0.22631.6936/10.0.25398.2274/10.0.26100.32690/10.0.26200.8246

Timelineinfo

04/14/2026 VulDB entry created
04/14/2026 +0 days Advisory disclosed
04/14/2026 +0 days Countermeasure disclosed
06/01/2026 +47 days VulDB entry last update