diff --git a/ChangeLog b/ChangeLog
index a0fc6a0a98..a94e8bfbe9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2026-10-13  Paul Eggert  <eggert@cs.ucla.edu>
+
+	regex-tests: pacify -Wformat-overflow
+	Problem and fix reported by Pádraig Brady in:
+	https://lists.gnu.org/r/bug-gnulib/2026-10/msg00072.html
+	* tests/test-regex-el.c (main): Use %c not %s.
+
 2026-10-12  Arno Onken  <asnelt@asnelt.org>
 
 	regex: fold case in bracket fastmap only if RE_ICASE
diff --git a/tests/test-regex-el.c b/tests/test-regex-el.c
index 1e2589a3b2..d16b9eb3cd 100644
--- a/tests/test-regex-el.c
+++ b/tests/test-regex-el.c
@@ -80,7 +80,7 @@ main ()
           char pat[4];
           char const *lbrack = &"["[k];
           char const *rbrack = &"]"[k];
-          int patlen = sprintf (pat, "%s%s%s", lbrack, str[i], rbrack);
+          int patlen = sprintf (pat, "%s%c%s", lbrack, str[i][0], rbrack);
           re_set_syntax (RE_ICASE);
           memset (&regex, 0, sizeof regex);
           s = re_compile_pattern (pat, patlen, &regex);