Fix NUL truncation in the JSON parser

This fixes CVE-2026-33948.

src/util.c

@@ -312,13 +312,7 @@ static int jq_util_input_read_more(jq_util_input_state *state) {
       if (p != NULL)
         state->current_line++;
 
-      if (p == NULL && state->parser != NULL) {
+      if (p == NULL && feof(state->current_input)) {
-        /*
-         * There should be no NULs in JSON texts (but JSON text
-         * sequences are another story).
-         */
-        state->buf_valid_len = strlen(state->buf);
-      } else if (p == NULL && feof(state->current_input)) {
         size_t i;
 
         /*

tests/shtest

@@ -880,4 +880,10 @@ $JQ -nf $d/prog.jq 2> $d/out && {
 }
 diff $d/out $d/expected
 
+# CVE-2026-33948: No NUL truncation in the JSON parser
+if printf '{}\x00{}' | $JQ >/dev/null 2> /dev/null; then
+  printf 'Error expected but jq exited successfully\n' 1>&2
+  exit 1
+fi
+
 exit 0