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CVE-2026-26955

HighCVSS 8.8 / 10
Published Feb 25, 2026·Last modified May 5, 2026
Affected Components(0)

No affected components available

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, a malicious RDP server can trigger a heap buffer overflow in FreeRDP clients using the GDI surface pipeline (e.g., xfreerdp) by sending an RDPGFX ClearCodec surface command with an out-of-bounds destination rectangle. The gdi_SurfaceCommand_ClearCodec() handler does not call is_within_surface() to validate the command rectangle against the destination surface dimensions, allowing attacker-controlled cmd->left/cmd->top (and subcodec rectangle offsets) to reach image copy routines that write into surface->data without bounds enforcement. The OOB write corrupts an adjacent gdiGfxSurface struct's codecs* pointer with attacker-controlled pixel data, and corruption of codecs* is sufficient to reach an indirect function pointer call (NSC_CONTEXT.decode at nsc.c:500) on a subsequent codec command — full instruction pointer (RIP) control demonstrated in exploitability harness. Users should upgrade to version 3.23.0 to receive a patch.

Risk Scores
Base Score
8.8

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. The attacker needs the user to perform some action, like clicking a link. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
8.1

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.54%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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