diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index 23eae2239..558e7048f 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -5371,7 +5371,7 @@ static ssize_t quic_dgram_read(struct buffer *buf, size_t len, void *owner,
 	if (dgram_ctx.qc)
 		dgram_ctx.qc->rx.bytes += len;
 
-	return pos - (unsigned char *)buf;
+	return pos - (unsigned char *)b_head(buf);
 
  err:
 	return -1;