CVE-2026-109952 FreeRDP 3.0.0 before 3.32.0 Security Protocol Downgrade via Negotiation Response
A malicious server or man-in-the-middle can downgrade security protocols to bypass NLA pinning and capture cleartext passwords from FreeRDP clients.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-109952?
CVE-2026-109952 is a medium-severity vulnerability in Freerdp Freerdp, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
The FreeRDP client 3.0.0 before 3.32.0 does not check a server-selected PROTOCOL_RDSTLS or PROTOCOL_HYBRID_EX against its enabled protocol set in nego_process_negotiation_response(), allowing a security protocol downgrade. A malicious server or man-in-the-middle can select RDSTLS to override /sec:nla pinning, complete authentication with an all-zero cookie, and receive the user's cleartext password in the Client Info PDU.
Weakness: CWE-757
Which versions are affected by CVE-2026-109952?
It affects 1 product.
Products include Freerdp Freerdp.
How do I fix CVE-2026-109952?
Upgrade to a fixed version.
Is CVE-2026-109952 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109952 exists.
Other vulnerabilities in Freerdp Freerdp
- CVE-2021-37594 Other in n/a
- CVE-2021-37595 Other in n/a
- CVE-2026-67305 FreeRDP Windows Client before 3.29.0 Heap Buffer Overflow via Cliprdr
- CVE-2026-66402 FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass
- CVE-2026-67289 FreeRDP before 3.29.0 HTTP Proxy Request Injection via Redirection
Sources
Also known as DEBIAN-CVE-2026-109952, GHSA-c6qf-gf3v-f99j, GHSA-qq23-mqmv-pc65, UBUNTU-CVE-2026-109952.