Vulnerability · Published Sep 15, 2026 · Assigned by VulnCheck

CVE-2026-91958FreeRDP 3.11.0 through 3.30.0 Heap Buffer Overflow via Monitor Index

Medium 6.6

In plain English

A medium-severity out-of-bounds read in FreeRDP from FreeRDP. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.6Medium

Exploit odds (30 days)0.2%top 90.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

FreeRDP versions before 3.31.0 fail to validate MonitorIds array values when parsing RDP connection files, allowing unbounded array indexing in xf_detect_monitors. Attackers can craft a malicious RDP file with an out-of-range selectedmonitors value to trigger out-of-bounds heap read and write operations when opened in xfreerdp.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:13	freerdp3	no fix listed	DEBIAN-CVE-2026-91958
Debian:14	freerdp3	3.31.0+dfsg-1	DEBIAN-CVE-2026-91958
Ubuntu:22.04:LTS	freerdp2	no fix listed	UBUNTU-CVE-2026-91958
Ubuntu:24.04:LTS	freerdp3	3.31.0+dfsg-0ubuntu0.24.04.1	UBUNTU-CVE-2026-91958
Ubuntu:26.04:LTS	freerdp3	3.31.0+dfsg-0ubuntu0.26.04.1	UBUNTU-CVE-2026-91958

Affected products (as reported)

Vendor	Product	Versions
FreeRDP	FreeRDP	3.11.0 – before 3.31.0

Weakness: CWE-125 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

References

GitHub Security Advisory (GHSA-23pf-q83q-x45r) vendor-advisory
VulnCheck Advisory: FreeRDP 3.11.0 through 3.30.0 Heap Buffer Overflow via Monitor Index third-party-advisory