What’s Vulnerable › Vulnerabilities

CVE-2021-41159: Improper client input validation for FreeRDP gateway connections allows to overwrite memory

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-21 · updated 2026-06-17
• Weakness: CWE-787

Description

FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. All FreeRDP clients prior to version 2.4.1 using gateway connections (`/gt:rpc`) fail to validate input data. A malicious gateway might allow client memory to be written out of bounds. This issue has been resolved in version 2.4.1. If you are unable to update then use `/gt:http` rather than /gt:rdp connections if possible or use a direct connection without a gateway.

Affected products

• Fedoraproject Fedora: 35
• FreeRDP: before 2.4.1 — fixed in 2.4.1

How to fix

Upgrade to a fixed version: FreeRDP 2.4.1. Check the vendor advisory for mitigations.

References

• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-vh34-m9h7-95xq
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DWJXQOWKNR7O5HM2HFJOM4GBUFPTE3RG/
• https://security.gentoo.org/glsa/202210-24
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-vh34-m9h7-95xq
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DWJXQOWKNR7O5HM2HFJOM4GBUFPTE3RG/
• https://security.gentoo.org/glsa/202210-24

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