Bug 2443132 (CVE-2026-26955)

Summary: CVE-2026-26955 freerdp: FreeRDP: Arbitrary code execution via heap buffer overflow in GDI surface pipeline
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in FreeRDP, a free implementation of the Remote Desktop Protocol (RDP). A malicious RDP server can exploit a heap buffer overflow vulnerability by sending a specially crafted graphics command to a FreeRDP client. This allows the server to write data outside of its intended memory region, potentially leading to arbitrary code execution on the client system. The vulnerability occurs because the client does not properly validate the dimensions of incoming graphics commands.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2443144, 2443146, 2443145    
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Description OSIDB Bzimport 2026-02-26 21:04:09 UTC 
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.