--- a/sys/dev/drm/amd/amdgpu/amdgpu_uvd.c
+++ b/sys/dev/drm/amd/amdgpu/amdgpu_uvd.c
@@ -528,6 +528,17 @@
 	unsigned image_size, tmp, min_dpb_size, num_dpb_buffer;
 	unsigned min_ctx_size = ~0;
 
+	/* Reject invalid dimensions: prevents both the divide-by-zero on
+	 * fs_in_mb (DF-1595) and the u32 overflow of image_size /
+	 * min_dpb_size / min_ctx_size for large width*height (DF-4404),
+	 * which otherwise bypasses the DPB/ctx buffer size validation.
+	 * Mirrors upstream Linux 05e1387d151f + 3e41d26c70b0. */
+	if (width < 16 || height < 16 || width > 4096 || height > 4096) {
+		DRM_ERROR("Invalid UVD decoding dimensions (%d x %d)!\n",
+			  width, height);
+		return -EINVAL;
+	}
+
 	image_size = width * height;
 	image_size += image_size / 2;
 	image_size = ALIGN(image_size, 1024);