diff --git a/src/dec/buffer_dec.c b/src/dec/buffer_dec.c

index 75eb3c4..3cd94eb 100644

--- a/src/dec/buffer_dec.c

+++ b/src/dec/buffer_dec.c

@@ -74,7 +74,8 @@

   } else {    // RGB checks

     const WebPRGBABuffer* const buf = &buffer->u.RGBA;

     const int stride = abs(buf->stride);

-    const uint64_t size = MIN_BUFFER_SIZE(width, height, stride);

+    const uint64_t size =

+        MIN_BUFFER_SIZE(width * kModeBpp[mode], height, stride);

     ok &= (size <= buf->size);

     ok &= (stride >= width * kModeBpp[mode]);

     ok &= (buf->rgba != NULL);