From: Stefan Metzmacher <metze@samba.org>
Date: Fri, 8 May 2026 21:27:35 +0000 (+0200)
Subject: CVE-2026-4480: s3:testparm: warn about 'print command' %J usage
X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=c6ecded7002c112ffd239e6082ab37e8eb7a4ff5;p=thirdparty%2Fsamba.git

CVE-2026-4480: s3:testparm: warn about 'print command' %J usage

BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
---

diff --git a/source3/utils/testparm.c b/source3/utils/testparm.c
index af3a253fc28..156a78c0f69 100644
--- a/source3/utils/testparm.c
+++ b/source3/utils/testparm.c
@@ -953,6 +953,14 @@ static void do_per_share_checks(int s)
 			"parameter is ignored when using CUPS libraries.\n\n",
 			lp_servicename(talloc_tos(), lp_sub, s));
 	}
+	if (talloc_string_sub_mixed_quoting(lp_print_command(s), 'J')) {
+		fprintf(stderr,
+			"WARNING: Service %s defines a 'print command' "
+			"with mixed quoting and %%J.\n"
+			"CVE-2026-4480 changed the way %%J substitution works.\n"
+			"You should use single quotes (directly) around '%%J'.\n\n",
+			lp_servicename(talloc_tos(), lp_sub, s));
+	}
 
 	vfs_objects = lp_vfs_objects(s);
 	if (vfs_objects && str_list_check(vfs_objects, "fruit")) {