What is CVE-2026-121963?

CVE-2026-121963 is a medium-severity vulnerability in Freerdp, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 5.9/10. Published 2026-11-04.

How severe is CVE-2026-121963?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Use After Free in Freerdp

CVE-2026-121963

FreeRDP before 3.32.2 contains a use-after-free vulnerability in the asynchronous dynamic rdpsnd channel that allows malicious RDP servers to trigger freed callback access by closing the channel with queued audio PDUs. Attackers can send a training PDU then close the channel so the playback thread reads the freed callback in rdpsnd_virtual_channel_write, crashing the client.

Vulnerability class: Race Condition

Published 2026-11-04 · last modified 2026-11-05.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/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)

References

github.com/FreeRDP/FreeRDP/security/advisories/GHSA-cx9c-q4jc-wm6c (Exploit, vendor-advisory, Vendor Advisory)
www.vulncheck.com/advisories/freerdp-before-3.32.2-use-after-free-via-dynamic-r… (Third Party Advisory, third-party-advisory)

Frequently asked questions

What is CVE-2026-121963?: CVE-2026-121963 is a medium-severity vulnerability in Freerdp, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 5.9/10. Published 2026-11-04.
How severe is CVE-2026-121963?: Medium severity. CVSS v3 base score is 5.9 out of 10.