What’s Vulnerable › Vulnerabilities

CVE-2026-33952: FreeRDP: DoS via WINPR_ASSERT in rts_read_auth_verifier_no_checks

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-03-30 · updated 2026-06-17
• Weakness: CWE-617

Description

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.

Affected products

• FreeRDP: before 3.24.2 — fixed in 3.24.2

How to fix

Upgrade to a fixed version: FreeRDP 3.24.2. Check the vendor advisory for mitigations.

References

• https://github.com/FreeRDP/FreeRDP/commit/4ac0b6467d371a1ad47c1f751c5b305e4c068adb
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-4v4p-9v5x-hc93

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