Is CVE-2026-23534 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-23534 being exploited in the wild.

How severe is CVE-2026-23534?

Critical severity, with a CVSS score of 9.8, published 19 January 2026.

Is there a fix for CVE-2026-23534?

A patch was published on 2026-01-19: FreeRDP version 3.21.0 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-23534 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-23534?

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.

CVE-2026-23534: FreeRDP heap buffer overflow in ClearCodec bands decode path

CVE-2026-23534 · Severity: critical · CVSS 9.8 · Published 2026-01-19

FreeRDP is an open-source tool used to connect to remote computers via the Remote Desktop Protocol. A security flaw in how the software processes image data could allow a malicious server to crash a user's connection or potentially take control of the user's computer. This risk is particularly high when connecting to untrusted or compromised remote servers.

Technologies: FreeRDP. Vendors: FreeRDP.

Quick answers

Is CVE-2026-23534 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-23534 being exploited in the wild.
How severe is CVE-2026-23534?: Critical severity, with a CVSS score of 9.8, published 19 January 2026.
Which products and versions are affected?: FreeRDP < 3.21.0.
Is there a fix for CVE-2026-23534?: A patch was published on 2026-01-19: FreeRDP version 3.21.0 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-23534 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-23534?: 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.

Technical details

A heap-based buffer overflow exists in FreeRDP's ClearCodec implementation within the `clear_decompress_bands_data` function in `libfreerdp/codec/clear.c`. The vulnerability is triggered by insufficient validation of `xStart`, `xEnd`, `yStart`, and `yEnd` coordinates provided in a `WIRE_TO_SURFACE_PDU_1` stream. Specifically, the code checks if coordinates are greater than the destination bounds but fails to account for coordinates equal to the bounds, leading to an out-of-bounds write during the `FreeRDPWriteColor_int` operation. An attacker controlling a malicious RDP server can exploit this to cause a denial-of-service or achieve remote code execution on the client. The issue is resolved in version 3.21.0.

Affected products

FreeRDP FreeRDP < 3.21.0
Red Hat Enterprise Linux 8, 9, 10

Timeline

2026-01-19: advisory: GitHub Security Advisory and NVD entry published
2026-01-19: patched: FreeRDP version 3.21.0 released
2026-02-05: patched: Red Hat released security updates for RHEL 9

References

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