Out-of-bounds write in FreeRDP - CVE-2026-22853

Vulnerability identifier: #VU122511

CSH Severity: High

CVSS v4: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-22853

CWE-ID: CWE-787

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing untrusted input within the ndr_read_uint8Array() function. A remote attacker can trick the victim into connecting to a malicious server, trigger an out-of-bounds write and execute arbitrary code on the target system.

FreeRDP
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support
Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support
Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support
Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support
Ubuntu
freerdp3 (Ubuntu package)
freerdp (Red Hat package)

Install updates from vendor's website.

FreeRDP - update to 3.20.1
freerdp3 (Ubuntu package) - addressed in versions 3.5.1+dfsg1-0ubuntu1.4, 3.16.0+dfsg-2ubuntu0.3
freerdp (Red Hat package) - addressed in versions 3.10.3-3.el10_0.2, 3.10.3-5.el10_1.2

• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-47v9-p4gp-w5ch

• Multiple vulnerabilities in FreeRDP
• Red Hat Enterprise Linux 10 update for freerdp
• Red Hat Enterprise Linux 10 update for freerdp
• Ubuntu update for freerdp3