What is CVE-2026-121400?

CVE-2026-121400 is a medium-severity vulnerability in Freerdp, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2026-11-03.

How severe is CVE-2026-121400?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Freerdp

CVE-2026-121400

FreeRDP before 3.32.2 contains a denial-of-service vulnerability in rdg_process_control_packet that allows a malicious RD Gateway to exhaust client CPU by sending an incomplete keepalive control packet. Attackers completing the RDG tunnel-open exchange then send an eight-byte header with packetLength 0xFFFF and withhold the body, causing an unbounded no-progress read loop that spins one client thread at full CPU.

Published 2026-11-03 · last modified 2026-11-03.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Freerdp

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

References

github.com/FreeRDP/FreeRDP/security/advisories/GHSA-x4x6-2hrm-hvq9 (vendor-advisory, Vendor Advisory)
www.vulncheck.com/advisories/freerdp-before-3.32.2-cpu-exhaustion-via-rdg-contr… (Third Party Advisory, third-party-advisory)

Frequently asked questions

What is CVE-2026-121400?: CVE-2026-121400 is a medium-severity vulnerability in Freerdp, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2026-11-03.
How severe is CVE-2026-121400?: Medium severity. CVSS v3 base score is 6.5 out of 10.