Vulnerability · Published Mar 30, 2026 · Assigned by GitHub_M
CVE-2026-33952FreeRDP: DoS via WINPR_ASSERT in rts_read_auth_verifier_no_checks
Medium 6.5
In plain English
A medium-severity security flaw in FreeRDP from FreeRDP. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | freerdp | 3.24.2-r0 | ALPINE-CVE-2026-33952 |
| Alpine:v3.24 | freerdp | 3.24.2-r0 | ALPINE-CVE-2026-33952 |
| Debian:12 | freerdp2 | no fix listed | DEBIAN-CVE-2026-33952 |
| Debian:13 | freerdp3 | 3.15.0+dfsg-2.1+deb13u2 | DEBIAN-CVE-2026-33952 |
| Debian:14 | freerdp3 | 3.24.2+dfsg-1 | DEBIAN-CVE-2026-33952 |
| Ubuntu:22.04:LTS | freerdp2 | no fix listed | UBUNTU-CVE-2026-33952 |
| Ubuntu:24.04:LTS | freerdp3 | 3.30.0+dfsg-0ubuntu0.24.04.1 | USN-8561-1 |
| Ubuntu:24.04:LTS | freerdp3 | 3.30.0+dfsg-0ubuntu0.24.04.1 | UBUNTU-CVE-2026-33952 |
| Ubuntu:25.10 | freerdp3 | no fix listed | UBUNTU-CVE-2026-33952 |
| Ubuntu:26.04:LTS | freerdp3 | 3.30.0+dfsg-0ubuntu0.26.04.1 | USN-8561-1 |
Affected products (as reported)
Weakness: CWE-617 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H