Quick answers
- Is CVE-2026-121406 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-121406 being exploited in the wild.
- How severe is CVE-2026-121406?
- Medium severity, with a CVSS score of 4.3, published 3 November 2026.
- Which products and versions are affected?
- FreeRDP before 3.32.2.
- Is there a fix for CVE-2026-121406?
- Yes: fixed in 3.32.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-121406 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-121406?
- Check whether you run FreeRDP at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: 3.32.2
Technical details
The rdpgfx_on_data_received function in FreeRDP checks only for negative status codes from zgfx_decompress, allowing a zero-output successful decompression (which returns a null pointer) to proceed to Stream_StaticConstInit. This function contains a WINPR_ASSERT(buffer) that aborts when buffer is null, triggered when verbose WinPR assertions are enabled (the CMake default). An unauthenticated attacker can send a three-byte ZGFX payload (E0 20 00) or seven-byte empty multipart payload after session activation to trigger client termination.
Affected products
- FreeRDP FreeRDP before 3.32.2
Timeline
- 2026-10-19: disclosed: GitHub Security Advisory GHSA-2c9x-4gr7-hrwx published
- 2026-11-03: advisory: NVD and VulnCheck advisories published