CVE-2026-33952: FreeRDP: DoS via WINPR_ASSERT in rts_read_auth_verifier_no_checks
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, an unvalidated authlength field read from the network triggers a WINPRASSERT() failure in rtsreadauthverifiernochecks(), causing any FreeRDP client connecting through a malicious RDP Gateway to crash with SIGABRT. This is a pre-authentication denial of service affecting all FreeRDP clients using RPC-over-HTTP gateway transport. The assertion is active in default release builds (WITHVERBOSEWINPRASSERT=ON). This issue has been patched in version 3.24.2.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
alpine/freerdpto a version that resolves this vulnerability.Fixed in 3.24.2-r0 - Upgrade
Upgrade
FreeRDPto a version that resolves this vulnerability.Fixed in 3.24.2
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33952?
CVE-2026-33952 is classified as a denial of service (DoS) vulnerability affecting FreeRDP versions prior to 3.24.2.
How do I fix CVE-2026-33952?
To mitigate CVE-2026-33952, upgrade FreeRDP to version 3.24.2 or later.
What causes CVE-2026-33952?
CVE-2026-33952 occurs due to an unvalidated auth_length field read from the network that triggers a WINPR_ASSERT failure.
Who is affected by CVE-2026-33952?
Users of FreeRDP versions prior to 3.24.2 are affected by CVE-2026-33952.
What are the potential impacts of CVE-2026-33952?
The potential impact of CVE-2026-33952 includes service disruption resulting from a denial of service condition in FreeRDP.