Bug 2447376 (CVE-2026-31806)

Summary: CVE-2026-31806 freerdp: FreeRDP: Arbitrary code execution via crafted Remote Desktop Protocol (RDP) server messages
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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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). The `gdi_surface_bits()` function, which processes `SURFACE_BITS_COMMAND` messages, does not properly validate image dimensions (`bmp.width` and `bmp.height`) provided by a malicious RDP server. This can lead to a heap buffer overflow during bitmap decoding and memory operations. A remote attacker could exploit this to overwrite adjacent memory, potentially resulting in arbitrary code execution.
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Bug Depends On: 2447392, 2447394, 2447393    
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Description OSIDB Bzimport 2026-03-13 18:04:13 UTC 
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0,  the gdi_surface_bits() function processes SURFACE_BITS_COMMAND messages sent by the RDP server. When the command is handled using NSCodec, the bmp.width and bmp.height values provided by the server are not properly validated against the actual desktop dimensions. A malicious RDP server can supply crafted bmp.width and bmp.height values that exceed the expected surface size. Because these values are used during bitmap decoding and memory operations without proper bounds checking, this can lead to a heap buffer overflow. Since the attacker can also control the associated pixel data transmitted by the server, the overflow may be exploitable to overwrite adjacent heap memory. This vulnerability is fixed in 3.24.0.