Vulnerability · Published Sep 15, 2026 · Assigned by VulnCheck

CVE-2026-91948FreeRDP before 3.31.0 Out-of-bounds Write via SHOW_PROTOCOL

High 7.5

In plain English

A high-severity security flaw in FreeRDP from FreeRDP. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.6%top 51.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

FreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in server-side static virtual channel handling when CHANNEL_OPTION_SHOW_PROTOCOL is enabled. Authenticated clients can queue oversized channel messages that cause buffer underflow and corrupt heap memory including live pointers, potentially enabling code execution.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:14	freerdp3	3.31.0+dfsg-1	DEBIAN-CVE-2026-91948
Ubuntu:22.04:LTS	freerdp2	no fix listed	UBUNTU-CVE-2026-91948
Ubuntu:24.04:LTS	freerdp3	3.31.0+dfsg-0ubuntu0.24.04.1	UBUNTU-CVE-2026-91948
Ubuntu:26.04:LTS	freerdp3	3.31.0+dfsg-0ubuntu0.26.04.1	UBUNTU-CVE-2026-91948

Affected products (as reported)

Vendor	Product	Versions
FreeRDP	FreeRDP	3.28.0 – before 3.31.0

Weakness: CWE-191 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

References

GitHub Security Advisory (GHSA-9jcm-x588-gh26) vendor-advisory
Patch Commit patch
VulnCheck Advisory: FreeRDP before 3.31.0 Out-of-bounds Write via SHOW_PROTOCOL third-party-advisory