NULL pointer dereference in FreeRDP - #VU164448
Published: November 10, 2026
Vulnerability identifier: #VU164448
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service by crashing the FreeRDP proxy process and interrupting all sessions it hosts.
The vulnerability exists due to a null pointer dereference in pf_server_refresh_rect and pf_server_suppress_output when processing pre-activation data without checking backend context availability or connection state. A remote attacker can complete channel joining, security negotiation and licensing, then send a REFRESH_RECT or SUPPRESS_OUTPUT data PDU before Confirm Active to crash the proxy.
Affected software
FreeRDP
Remediation
Install security update from vendor's website.
FreeRDP - update to 3.33.0