--- ext/Digest/MD5/MD5_orig.xs  2007-08-15 16:04:42.784446351 +0200
+++ ext/Digest/MD5/MD5.xs       2007-08-15 16:29:18.914177790 +0200
@@ -84,6 +84,8 @@ extern "C" {
    #define SvPVbyte SvPV
 #endif

+#define SvPVbyte_save(sv, lp) SvPVbyte(sv_mortalcopy(sv), lp)
+
 #ifndef dTHX
    #define pTHX_
    #define aTHX_
@@ -613,7 +615,7 @@ add(self, ...)
        STRLEN len;
     PPCODE:
        for (i = 1; i < items; i++) {
-           data = (unsigned char *)(SvPVbyte(ST(i), len));
+           data = (unsigned char *)(SvPVbyte_save(ST(i), len));
            MD5Update(context, data, len);
        }
        XSRETURN(1);  /* self */
@@ -707,7 +709,7 @@ md5(...)
                }
            }
            else if (items > 1) {
-               data = (unsigned char *)SvPVbyte(ST(0), len);
+               data = (unsigned char *)SvPVbyte_save(ST(0), len);
                if (len == 11 && memEQ("Digest::MD5", data, 11)) {
                    msg = "probably called as class method";
                }
@@ -720,7 +722,7 @@ md5(...)
        }

        for (i = 0; i < items; i++) {
-           data = (unsigned char *)(SvPVbyte(ST(i), len));
+           data = (unsigned char *)(SvPVbyte_save(ST(i), len));
            MD5Update(&ctx, data, len);
        }
        MD5Final(digeststr, &ctx);