Microsoft Windows up to Server 2025 FTP Service heap-based overflow

Summaryinfo

A vulnerability, which was classified as very critical, has been found in Microsoft Windows up to Server 2025. Affected is an unknown function of the component FTP Service. This manipulation causes heap-based overflow. This vulnerability is handled as CVE-2026-49172. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Microsoft Windows up to Server 2025. It has been declared as very critical. Affected by this vulnerability is an unknown functionality of the component FTP Service. The manipulation with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Heap-based buffer overflow in Windows FTP Service allows an unauthorized attacker to execute code over a network.

The advisory is shared at msrc.microsoft.com. This vulnerability is known as CVE-2026-49172 since 05/28/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $25k-$100k at the moment (estimation calculated on 07/15/2026).

The vulnerability scanner Nessus provides a plugin with the ID 326875 (KB5099538: Windows 10 version 1809 / Windows Server 2019 Security Update (July 2026)), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at Tenable (326875). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Operating System

Vendor

• Microsoft

Name

• Windows

Version

• 10 21H2
• 10 22H2
• 10 1607
• 10 1809
• 11 23H2
• 11 24H2
• 11 25H2
• 11 26H1
• Server 2019
• Server 2022
• 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

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion