diff --git a/pkgs/by-name/li/libarchive/fix-darwin-tmpdir-handling.patch b/pkgs/by-name/li/libarchive/fix-darwin-tmpdir-handling.patch
new file mode 100644
index 000000000000..3e88c15dbdf2
--- /dev/null
+++ b/pkgs/by-name/li/libarchive/fix-darwin-tmpdir-handling.patch
@@ -0,0 +1,22 @@
+From 87bbe8ec8d343c70ae42ccb9606ec80ad73ceffb Mon Sep 17 00:00:00 2001
+From: Emily <hello@emily.moe>
+Date: Tue, 29 Jul 2025 16:53:15 +0100
+Subject: [PATCH] Fix setup_mac_metadata when TMPDIR does not end with a slash
+
+---
+ libarchive/archive_read_disk_entry_from_file.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/libarchive/archive_read_disk_entry_from_file.c b/libarchive/archive_read_disk_entry_from_file.c
+index 19d049770b..87389642db 100644
+--- a/libarchive/archive_read_disk_entry_from_file.c
++++ b/libarchive/archive_read_disk_entry_from_file.c
+@@ -364,7 +364,7 @@ setup_mac_metadata(struct archive_read_disk *a,
+ 		tempdir = _PATH_TMP;
+ 	archive_string_init(&tempfile);
+ 	archive_strcpy(&tempfile, tempdir);
+-	archive_strcat(&tempfile, "tar.md.XXXXXX");
++	archive_strcat(&tempfile, "/tar.md.XXXXXX");
+ 	tempfd = mkstemp(tempfile.s);
+ 	if (tempfd < 0) {
+ 		archive_set_error(&a->archive, errno,
diff --git a/pkgs/by-name/li/libarchive/package.nix b/pkgs/by-name/li/libarchive/package.nix
index 640914afd9a0..a3e0d592c26e 100644
--- a/pkgs/by-name/li/libarchive/package.nix
+++ b/pkgs/by-name/li/libarchive/package.nix
@@ -48,6 +48,11 @@ stdenv.mkDerivation (finalAttrs: {
       url = "https://github.com/libarchive/libarchive/commit/489d0b8e2f1fafd3b7ebf98f389ca67462c34651.patch?full_index=1";
       hash = "sha256-r+tSJ+WA0VKCjg+8MfS5/RqcB+aAMZ2dK0YUh+U1q78=";
     })
+    # Fix the tests on Darwin when `$TMPDIR` does not end with a slash
+    # and its parent directory is not writable by the build user, as on
+    # Nix ≥ 2.30.0 and Lix ≥ 2.91.2, ≥ 2.92.2, ≥ 2.93.1.
+    # <https://github.com/libarchive/libarchive/pull/2708>
+    ./fix-darwin-tmpdir-handling.patch
   ];
 
   outputs = [