Fixes CVE-2026-56017, which would SEGFAULT Perl.

Changes

@@ -1,6 +1,9 @@
 Revision history for Perl extension JavaScript::Minifier::XS.
 
 {{$NEXT}}
+    - Fixes CVE-2026-56017, which caused Perl to SEGFAULT when calling
+      minify().  Thanks to CPANSec for raising the issue, and providing a
+      prototype fix.
 
 0.15      2021-10-15 20:21:23-07:00 America/Vancouver
     - GH#8 - preserve newlines when collapsing whitespace; if a block of

XS.xs

@@ -446,13 +446,14 @@ Node* JsTokenizeString(JsDoc* doc, const char* string) {
                 char ch = 0;
 
                 /* find last non-whitespace, non-comment node */
-                while (nodeIsWHITESPACE(last) || nodeIsCOMMENT(last))
+                while (last && (nodeIsWHITESPACE(last) || nodeIsCOMMENT(last)))
                     last = last->prev;
 
-                ch = last->contents[last->length-1];
+                if (last && (last->length > 0))
+                    ch = last->contents[last->length-1];
 
                 /* see if we're "division" or "regexp" */
-                if (nodeIsIDENTIFIER(last) && nodeEquals(last, "return")) {
+                if (last && nodeIsIDENTIFIER(last) && nodeEquals(last, "return")) {
                     /* returning a regexp from a function */
                     _JsExtractLiteral(doc, node);
                 }

t/CVE-2026-56017.t

@@ -0,0 +1,14 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use Test::More;
+use JavaScript::Minifier::XS qw(minify);
+
+###############################################################################
+# CVE-2026-56017
+eval { minify('/') };
+pass 'minified the JS without SEGFAULTing';
+
+###############################################################################
+done_testing();