From 51929613e6897489736a35eaaf14a3accf143963 Mon Sep 17 00:00:00 2001
From: Gyorgy Sarvari <skandigraun@gmail.com>
Date: Thu, 15 Jan 2026 12:04:36 +0100
Subject: [PATCH] properly clamp SurfaceToSurface

From: akallabeth <akallabeth@posteo.net>

CVE: CVE-2026-23532
Upstream-Status: Backport [https://github.com/FreeRDP/FreeRDP/commit/c4a7c371342edf0d307cea728f56d3302f0ab38c]
Signed-off-by: Gyorgy Sarvari <skandigraun@gmail.com>
---
 libfreerdp/gdi/gfx.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/libfreerdp/gdi/gfx.c b/libfreerdp/gdi/gfx.c
index 3970715e0..812568bbb 100644
--- a/libfreerdp/gdi/gfx.c
+++ b/libfreerdp/gdi/gfx.c
@@ -1175,7 +1175,6 @@ static UINT gdi_SurfaceToSurface(RdpgfxClientContext* context,
 	UINT status = ERROR_INTERNAL_ERROR;
 	UINT16 index;
 	BOOL sameSurface;
-	UINT32 nWidth, nHeight;
 	const RECTANGLE_16* rectSrc;
 	RECTANGLE_16 invalidRect;
 	gdiGfxSurface* surfaceSrc;
@@ -1199,8 +1198,8 @@ static UINT gdi_SurfaceToSurface(RdpgfxClientContext* context,
 	if (!is_rect_valid(rectSrc, surfaceSrc->width, surfaceSrc->height))
 		goto fail;
 
-	nWidth = rectSrc->right - rectSrc->left;
-	nHeight = rectSrc->bottom - rectSrc->top;
+	const UINT32 nWidth = rectSrc->right - rectSrc->left;
+	const UINT32 nHeight = rectSrc->bottom - rectSrc->top;
 
 	for (index = 0; index < surfaceToSurface->destPtsCount; index++)
 	{
@@ -1209,8 +1208,10 @@ static UINT gdi_SurfaceToSurface(RdpgfxClientContext* context,
 		if (!is_rect_valid(&rect, surfaceDst->width, surfaceDst->height))
 			goto fail;
 
+		const UINT32 rwidth = rect.right - rect.left;
+		const UINT32 rheight = rect.bottom - rect.top;
 		if (!freerdp_image_copy(surfaceDst->data, surfaceDst->format, surfaceDst->scanline,
-		                        destPt->x, destPt->y, nWidth, nHeight, surfaceSrc->data,
+		                        destPt->x, destPt->y, rwidth, rheight, surfaceSrc->data,
 		                        surfaceSrc->format, surfaceSrc->scanline, rectSrc->left,
 		                        rectSrc->top, NULL, FREERDP_FLIP_NONE))
 			goto fail;
