diff --git a/libgit2.spec b/libgit2.spec
index 6ad1c39..dca516a 100644
--- a/libgit2.spec
+++ b/libgit2.spec
@@ -59,6 +59,15 @@ find examples -name ".gitignore" -delete -print
 # Don't run "online" tests
 sed -i '/-sonline/s/^/#/' tests/libgit2/CMakeLists.txt
 
+%if 0%{?fedora} >= 40 || 0%{?rhel} >= 10
+# On Fedora 40+ and RHEL 10+, we're using zlib-ng rather than
+# zlib for compression. As a result, all of the pack tests fail
+# due to checking the hashes of the packed data against static
+# values that were created with zlib.
+# https://github.com/libgit2/libgit2/issues/6728
+sed -i 's/-xonline/-xonline -xpack/' tests/libgit2/CMakeLists.txt
+%endif
+
 # Remove bundled libraries (except libxdiff)
 pushd deps
 find . -maxdepth 1 -not -name xdiff -exec rm -rf {} ';'