diff --git a/mercurial/sslutil.py b/mercurial/sslutil.py
--- a/mercurial/sslutil.py
+++ b/mercurial/sslutil.py
@@ -24,6 +24,7 @@
     util,
 )
 from .utils import (
+    hashutil,
     resourceutil,
     stringutil,
 )
@@ -949,7 +950,7 @@
     # If a certificate fingerprint is pinned, use it and only it to
     # validate the remote cert.
     peerfingerprints = {
-        b'sha1': node.hex(hashlib.sha1(peercert).digest()),
+        b'sha1': node.hex(hashutil.sha1(peercert).digest()),
         b'sha256': node.hex(hashlib.sha256(peercert).digest()),
         b'sha512': node.hex(hashlib.sha512(peercert).digest()),
     }