Index: jsstr.c
===================================================================
RCS file: /cvsroot/mozilla/js/src/jsstr.c,v
retrieving revision 3.98
diff -p -u -8 -r3.98 jsstr.c
--- mozilla/js/src/jsstr.c	24 Feb 2005 18:59:41 -0000	3.98
+++ mozilla/js/src/jsstr.c	2 Apr 2005 02:36:30 -0000
@@ -1381,21 +1381,27 @@ find_replen(JSContext *cx, ReplaceData *
     if (lambda) {
         uintN argc, i, j, m, n, p;
         jsval *sp, *oldsp, rval;
         void *mark;
         JSStackFrame *fp;
         JSBool ok;
 
         /*
-         * Save the rightContext from the current regexp, since it
-         * gets stuck at the end of the replacement string and may
-         * be clobbered by a RegExp usage in the lambda function.
+         * Save the regExpStatics from the current regexp, since they may be
+         * clobbered by a RegExp usage in the lambda function.  Note that all
+         * members of JSRegExpStatics are JSSubStrings, so not GC roots, save
+         * input, which is rooted otherwise via argv[-1] in str_replace.
+         *
+         * We need to clear moreParens in the top-of-stack cx->regExpStatics
+         * to it won't be possibly realloc'ed, leaving the bottom-of-stack
+         * moreParens pointing to freed memory.
          */
-        JSSubString saveRightContext = cx->regExpStatics.rightContext;
+        JSRegExpStatics save = cx->regExpStatics;
+        cx->regExpStatics.moreParens = NULL;
 
         /*
          * In the lambda case, not only do we find the replacement string's
          * length, we compute repstr and return it via rdata for use within
          * do_replace.  The lambda is called with arguments ($&, $1, $2, ...,
          * index, input), i.e., all the properties of a regexp match array.
          * For $&, etc., we must create string jsvals from cx->regExpStatics.
          * We grab up stack space to keep the newborn strings GC-rooted.
@@ -1463,17 +1469,19 @@ find_replen(JSContext *cx, ReplaceData *
             } else {
                 rdata->repstr = repstr;
                 *sizep = JSSTRING_LENGTH(repstr);
             }
         }
 
       lambda_out:
         js_FreeStack(cx, mark);
-        cx->regExpStatics.rightContext = saveRightContext;
+        if (cx->regExpStatics.moreParens)
+            JS_free(cx, cx->regExpStatics.moreParens);
+        cx->regExpStatics = save;
         return ok;
     }
 #endif /* JS_HAS_REPLACE_LAMBDA */
 
     repstr = rdata->repstr;
     replen = JSSTRING_LENGTH(repstr);
     for (dp = rdata->dollar, ep = rdata->dollarEnd; dp;
          dp = js_strchr_limit(dp, '$', ep)) {