Heap-based buffer overflow in FreeRDP - CVE-2026-91953

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Main Vulnerability Database Vulnerabilities #VU146584

Heap-based buffer overflow in FreeRDP - CVE-2026-91953

Published: September 1, 2026 / Updated: September 16, 2026


Vulnerability identifier: #VU146584
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-91953
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to a heap-based buffer overflow in nego_send_negotiation_request when processing an oversized LB_LOAD_BALANCE_INFO routing token during connection negotiation. A remote attacker can send a crafted Server Redirection PDU to cause a denial of service.

The issue is reachable before any security protocol handshake completes, and user interaction is required to connect to a malicious server or a machine-in-the-middle server.


Affected software

FreeRDP
openEuler
freerdp
libwinpr-devel
libwinpr
freerdp-help
freerdp-devel
freerdp-debugsource
freerdp-debuginfo

How to mitigate CVE-2026-91953

Install security update from vendor's website.

FreeRDP - update to 3.31.0
freerdp - update to 2.11.8-11
libwinpr-devel - update to 2.11.8-11
libwinpr - update to 2.11.8-11
freerdp-help - update to 2.11.8-11
freerdp-devel - update to 2.11.8-11
freerdp-debugsource - update to 2.11.8-11
freerdp-debuginfo - update to 2.11.8-11

External References

Related Security Bulletins