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Vulnerability record · CVE-2026-91949 · published 15 September 2026

CVE-2026-91949: Freerdp vulnerability

Freerdp · Freerdp

FreeRDP server versions before 3.31.0 contain a protocol negotiation bypass vulnerability that allows unauthenticated attackers to establish RDSTLS connections despite server policy disabling them. Attackers can send incompatible protocol requests, receive negotiation failures, then complete TLS handshake and enter RDSTLS to bypass pre-authentication transport restrictions.

9.2 CVSS 4.0 Critical EPSS 0.56% · top 55.4% CWE-693 · CWE-693
9.2CVSS 4.0 base score
0.56%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 1 tagged exploit
24 Sep 2026Last modified by NVD

Description

FreeRDP server versions before 3.31.0 contain a protocol negotiation bypass vulnerability that allows unauthenticated attackers to establish RDSTLS connections despite server policy disabling them. Attackers can send incompatible protocol requests, receive negotiation failures, then complete TLS handshake and enter RDSTLS to bypass pre-authentication transport restrictions.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-x7v6-xfx3-52j6 ExploitMitigationVendor Advisory
https://www.vulncheck.com/advisories/freerdp-3.0.0-through-3.30.0-protocol-negotiation-bypass Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2026-31883Freerdp heap-based buffer overflow vulnerabilityFreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, a size_t underflow in the IMA-ADPCM and MS-ADPCM audio decoders lea…EPSS 0.32%9.8CVE-2024-32662Freerdp out-of-bounds read vulnerabilityFreeRDP is a free implementation of the Remote Desktop Protocol. FreeRDP based clients prior to version 3.5.1 are vulnerable to out-of-bounds read. T…EPSS 0.77%9.8CVE-2024-32659Freerdp out-of-bounds read vulnerabilityFreeRDP is a free implementation of the Remote Desktop Protocol. FreeRDP based clients prior to version 3.5.1 are vulnerable to out-of-bounds read if…EPSS 1.2%9.8CVE-2024-32658Freerdp out-of-bounds read vulnerabilityFreeRDP is a free implementation of the Remote Desktop Protocol. FreeRDP based clients prior to version 3.5.1 are vulnerable to out-of-bounds read. V…EPSS 1.4%9.8CVE-2024-32459Freerdp out-of-bounds read vulnerabilityFreeRDP is a free implementation of the Remote Desktop Protocol. FreeRDP based clients and servers that use a version of FreeRDP prior to 3.5.0 or 2.…EPSS 3.7%9.8CVE-2024-32460Freerdp out-of-bounds read vulnerabilityFreeRDP is a free implementation of the Remote Desktop Protocol. FreeRDP based based clients using `/bpp:32` legacy `GDI` drawing path with a version…EPSS 1.9%9.8CVE-2024-32039Freerdp integer overflow vulnerabilityFreeRDP is a free implementation of the Remote Desktop Protocol. FreeRDP based clients using a version of FreeRDP prior to 3.5.0 or 2.11.6 are vulner…EPSS 2.3%9.8CVE-2024-32040Freerdp vulnerabilityFreeRDP is a free implementation of the Remote Desktop Protocol. FreeRDP based clients that use a version of FreeRDP prior to 3.5.0 or 2.11.6 and hav…EPSS 1.9%

Source: NIST National Vulnerability Database (record CVE-2026-91949), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.