FreeRDP <3.24.2: Pre-auth DOS via unvalidated auth_length in RPC-over-HTTP
CVE-2026-33952 Published on March 30, 2026
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 auth_length field read from the network triggers a WINPR_ASSERT() failure in rts_read_auth_verifier_no_checks(), 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 (WITH_VERBOSE_WINPR_ASSERT=ON). This issue has been patched in version 3.24.2.
Vulnerability Analysis
CVE-2026-33952 is exploitable with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2026-33952. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is an assertion failure Vulnerability?
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
CVE-2026-33952 has been classified to as an assertion failure vulnerability or weakness.
Products Associated with CVE-2026-33952
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Affected Versions
FreeRDP Version < 3.24.2 is affected by CVE-2026-33952Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.