Commit 22b6266b for libheif

commit 22b6266bf03a9f016f84a9b57b80e1dd7c79d64a
Author: Dirk Farin <dirk.farin@gmail.com>
Date:   Sun Mar 15 14:42:26 2026 +0100

    fix overlay image with alpha channels with stride different from color channel (GHSA-hg7q-rjr2-8x46)

diff --git a/libheif/pixelimage.cc b/libheif/pixelimage.cc
index 85317ae0..2ce28579 100644
--- a/libheif/pixelimage.cc
+++ b/libheif/pixelimage.cc
@@ -1832,7 +1832,7 @@ Error HeifPixelImage::overlay(std::shared_ptr<HeifPixelImage>& overlay, int32_t
         for (uint32_t x = in_x0; x < in_w; x++) {
           uint8_t* outptr = &out_p[out_x0 + (out_y0 + y - in_y0) * out_stride + x];
           uint8_t in_val = in_p[in_x0 + y * in_stride + x];
-          uint8_t alpha_val = alpha_p[in_x0 + y * in_stride + x];
+          uint8_t alpha_val = alpha_p[in_x0 + y * alpha_stride + x];

           *outptr = (uint8_t) ((in_val * alpha_val + *outptr * (255 - alpha_val)) / 255);
         }