diff --git a/CHANGES b/CHANGES
index 8a3f610..069476b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,4 +1,10 @@
--- $MawkId: CHANGES,v 1.405 2024/12/10 01:25:31 tom Exp $
+-- $MawkId: CHANGES,v 1.409 2024/12/13 00:44:41 tom Exp $
+
+20241212
+	+ modify calls on stdtod() to disallow hexadecimal, infinite and
+	  not-a-number values unless the "--posix" option is given (report by
+	  Xose Vazquez Perez).
+	+ fix a regression in rexp3.c for pattern /^.$/ (cf: 20240819)
 
 20241209
 	+ modify use of OFMT when given a format such as %c which cannot fully
diff --git a/MANIFEST b/MANIFEST
index 35a7b9c..bfe0a7f 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -1,4 +1,4 @@
-MANIFEST for mawk, version t20241209
+MANIFEST for mawk, version t20241212
 --------------------------------------------------------------------------------
 MANIFEST                        this file
 ACKNOWLEDGMENT                  acknowledgements
diff --git a/cast.c b/cast.c
index e66ab9d..87cc60f 100644
--- a/cast.c
+++ b/cast.c
@@ -11,7 +11,7 @@ the GNU General Public License, version 2, 1991.
 ********************************************/
 
 /*
- * $MawkId: cast.c,v 1.32 2024/11/17 20:39:54 tom Exp $
+ * $MawkId: cast.c,v 1.34 2024/12/13 00:20:03 tom Exp $
  */
 
 #define Visible_CELL
@@ -26,50 +26,91 @@ the GNU General Public License, version 2, 1991.
 const int mpow2[NUM_CELL_TYPES] =
 {1, 2, 4, 8, 16, 32, 64, 128, 256, 512};
 
+#define isXDIGIT(c) \
+	(scan_code[(c)] == SC_DIGIT \
+	|| ((c) >= 'A' && (c) <= 'F') \
+	|| ((c) >= 'a' && (c) <= 'f'))
+
+static void
+string_to_double(CELL *cp)
+{
+    const char *q = string(cp)->str;
+    const char *r = string(cp)->len + q;
+
+    cp->dval = 0.0;
+
+    /* if non-posix, disallow hexadecimal, infinity and not-a-number */
+    if (!posix_space_flag) {
+	const char *s;
+
+	while ((q != r) && (scan_code[(UChar) q[0]] == SC_SPACE))
+	    q++;
+	if (q == r)
+	    goto done;
+	s = q;
+	if (scan_code[(UChar) q[0]] == SC_PLUS ||
+	    scan_code[(UChar) q[0]] == SC_MINUS)
+	    q++;
+	if (q[0] == '0') {
+	    if (q + 1 == r)	/* just "0" is legal */
+		goto done;
+	    if (q[1] == 'x' || q[1] == 'X') {
+		if (q + 2 == r)	/* "0x" by itself is zero */
+		    goto done;
+		if (isXDIGIT((UChar) q[2]))	/* ignore hexadecimal */
+		    goto done;
+	    }
+	} else if (scan_code[(UChar) q[0]] != SC_DIGIT && q[0] != '.') {
+	    goto done;		/* ignore non-number such as "inf" */
+	}
+	q = s;
+    }
+
+    errno = 0;
+#ifdef FPE_TRAPS_ON		/* look for overflow error */
+    cp->dval = strtod(q, (char **) 0);
+    if (errno && cp->dval != 0.0)	/* ignore underflow */
+	rt_error("overflow converting %s to double", q);
+#else
+    cp->dval = strtod(q, (char **) 0);
+#endif
+    free_STRING(string(cp));
+
+  done:
+    cp->type = C_DOUBLE;
+}
+
 void
 cast1_to_d(CELL *cp)
 {
     switch (cp->type) {
     case C_NOINIT:
 	cp->dval = 0.0;
+	cp->type = C_DOUBLE;
 	break;
 
     case C_DOUBLE:
-	return;
+	break;
 
     case C_MBSTRN:
     case C_STRING:
-	{
-	    register STRING *s = (STRING *) cp->ptr;
-
-	    errno = 0;
-#ifdef FPE_TRAPS_ON		/* look for overflow error */
-	    cp->dval = strtod(s->str, (char **) 0);
-	    if (errno && cp->dval != 0.0)	/* ignore underflow */
-		rt_error("overflow converting %s to double", s->str);
-#else
-	    cp->dval = strtod(s->str, (char **) 0);
-#endif
-	    free_STRING(s);
-	}
+	string_to_double(cp);
 	break;
 
     case C_STRNUM:
 	/* don't need to convert, but do need to free the STRING part */
 	free_STRING(string(cp));
+	cp->type = C_DOUBLE;
 	break;
 
     default:
 	bozo("cast on bad type");
     }
-    cp->type = C_DOUBLE;
 }
 
 void
 cast2_to_d(CELL *cp)
 {
-    register STRING *s;
-
     switch (cp->type) {
     case C_NOINIT:
 	cp->dval = 0.0;
@@ -83,17 +124,7 @@ cast2_to_d(CELL *cp)
 
     case C_MBSTRN:
     case C_STRING:
-	s = (STRING *) cp->ptr;
-
-	errno = 0;
-#ifdef FPE_TRAPS_ON		/* look for overflow error */
-	cp->dval = strtod(s->str, (char **) 0);
-	if (errno && cp->dval != 0.0)	/* ignore underflow */
-	    rt_error("overflow converting %s to double", s->str);
-#else
-	cp->dval = strtod(s->str, (char **) 0);
-#endif
-	free_STRING(s);
+	string_to_double(cp);
 	break;
 
     default:
@@ -117,17 +148,7 @@ cast2_to_d(CELL *cp)
 
     case C_MBSTRN:
     case C_STRING:
-	s = (STRING *) cp->ptr;
-
-	errno = 0;
-#ifdef FPE_TRAPS_ON		/* look for overflow error */
-	cp->dval = strtod(s->str, (char **) 0);
-	if (errno && cp->dval != 0.0)	/* ignore underflow */
-	    rt_error("overflow converting %s to double", s->str);
-#else
-	cp->dval = strtod(s->str, (char **) 0);
-#endif
-	free_STRING(s);
+	string_to_double(cp);
 	break;
 
     default:
@@ -321,6 +342,7 @@ check_strnum(CELL *cp)
 {
     char *temp;
     register unsigned char *s, *q;
+    char code;
 
     cp->type = C_STRING;	/* assume not C_STRNUM */
     s = (unsigned char *) string(cp)->str;
@@ -330,16 +352,27 @@ check_strnum(CELL *cp)
     if (s == q)
 	return;
 
-    while (scan_code[q[-1]] == SC_SPACE)
+    while ((code = scan_code[q[-1]]) == SC_SPACE)
 	q--;
-    if (scan_code[q[-1]] != SC_DIGIT &&
-	q[-1] != '.')
+    if (code != SC_DIGIT && code != SC_DOT)
 	return;
 
     switch (scan_code[*s]) {
-    case SC_DIGIT:
     case SC_PLUS:
     case SC_MINUS:
+	if (!posix_space_flag) {
+	    if ((code = scan_code[s[1]]) != SC_DIGIT && code != SC_DOT)
+		return;
+	}
+	/* FALLTHRU */
+    case SC_DIGIT:
+	if (!posix_space_flag) {
+	    if (*s == '0') {
+		if (s[1] == 'x' || s[1] == 'X')
+		    return;
+	    }
+	}
+	/* FALLTHRU */
     case SC_DOT:
 
 	errno = 0;
diff --git a/error.c b/error.c
index 44cbe84..8de7d2a 100644
--- a/error.c
+++ b/error.c
@@ -11,7 +11,7 @@ the GNU General Public License, version 2, 1991.
 ********************************************/
 
 /*
- * $MawkId: error.c,v 1.28 2024/08/29 00:19:40 tom Exp $
+ * $MawkId: error.c,v 1.29 2024/12/11 21:57:28 tom Exp $
  */
 
 #define Visible_CELL
@@ -156,6 +156,7 @@ yyerror(const char *s GCC_UNUSED)
 	    unexpected_char();
 	    break;
 
+#ifndef LCOV_UNUSED
 	case BAD_DECIMAL:
 	    compile_error(
 			     "syntax error in decimal constant %s",
@@ -167,6 +168,7 @@ yyerror(const char *s GCC_UNUSED)
 			     "syntax error at or near /%s/",
 			     string_buff);
 	    break;
+#endif
 
 	default:
 	    compile_error("syntax error");
@@ -306,15 +308,18 @@ type_to_str(int type)
     case ST_VAR:
 	retval = "variable";
 	break;
+#ifndef LCOV_UNUSED
     case ST_KEYWORD:
 	retval = "keyword";
 	break;
     case ST_BUILTIN:
 	retval = "builtin";
 	break;
+#endif
     case ST_ARRAY:
 	retval = "array";
 	break;
+#ifndef LCOV_UNUSED
     case ST_FIELD:
 	retval = "field";
 	break;
@@ -327,6 +332,7 @@ type_to_str(int type)
     case ST_FUNCT:
 	retval = "function";
 	break;
+#endif
     case ST_LOCAL_VAR:
 	retval = "local variable";
 	break;
diff --git a/package/debian/changelog b/package/debian/changelog
index 4411770..55112da 100644
--- a/package/debian/changelog
+++ b/package/debian/changelog
@@ -1,10 +1,10 @@
-mawk-cur (1.3.4-20241209) unstable; urgency=low
+mawk-cur (1.3.4-20241212) unstable; urgency=low
 
   * maintenance updates
 
- -- Thomas E. Dickey <dickey@invisible-island.net>  Mon, 09 Dec 2024 03:36:10 -0500
+ -- Thomas E. Dickey <dickey@invisible-island.net>  Tue, 10 Dec 2024 19:46:15 -0500
 
-mawk-cur (1.3.4-20241118) unstable; urgency=low
+mawk-cur (1.3.4-20241209) unstable; urgency=low
 
   * maintenance updates
 
diff --git a/package/freebsd/Makefile b/package/freebsd/Makefile
index 23c9dc7..28abe18 100644
--- a/package/freebsd/Makefile
+++ b/package/freebsd/Makefile
@@ -2,7 +2,7 @@
 # $FreeBSD: head/lang/mawk/Makefile 516890 2019-11-06 14:17:48Z wen $
 
 PORTNAME=	mawk
-DISTVERSION=	1.3.4.20241209
+DISTVERSION=	1.3.4.20241212
 CATEGORIES=	lang
 MASTER_SITES=	https://invisible-island.net/archives/${PORTNAME}/ \
 		https://invisible-mirror.net/archives/${PORTNAME}/
diff --git a/package/mawk.spec b/package/mawk.spec
index f2404e3..9167d29 100644
--- a/package/mawk.spec
+++ b/package/mawk.spec
@@ -1,9 +1,9 @@
 Summary: mawk - pattern scanning and text processing language
 %global AppProgram mawk
 %global AppVersion 1.3.4
-%global AppPatched 20241209
+%global AppPatched 20241212
 %global MySite https://invisible-island.net
-# $MawkId: mawk.spec,v 1.132 2024/12/10 01:25:31 tom Exp $
+# $MawkId: mawk.spec,v 1.134 2024/12/13 00:44:41 tom Exp $
 Name: %{AppProgram}
 Version: %{AppVersion}
 Release: %{AppPatched}
diff --git a/patchlev.h b/patchlev.h
index 9ecb0af..c7b677c 100644
--- a/patchlev.h
+++ b/patchlev.h
@@ -11,9 +11,9 @@ the GNU General Public License, version 2, 1991.
  */
 
 /*
- * $MawkId: patchlev.h,v 1.159 2024/12/10 01:25:31 tom Exp $
+ * $MawkId: patchlev.h,v 1.161 2024/12/13 00:44:41 tom Exp $
  */
 #define  PATCH_BASE	1
 #define  PATCH_LEVEL	3
 #define  PATCH_STRING	".4"
-#define  DATE_STRING    "20241209"
+#define  DATE_STRING    "20241212"
diff --git a/rexp2.c b/rexp2.c
index 7eea9d9..4803c0d 100644
--- a/rexp2.c
+++ b/rexp2.c
@@ -12,7 +12,7 @@ the GNU General Public License, version 2, 1991.
 ********************************************/
 
 /*
- * $MawkId: rexp2.c,v 1.46 2024/09/05 17:44:48 tom Exp $
+ * $MawkId: rexp2.c,v 1.48 2024/12/10 21:34:14 tom Exp $
  */
 
 /*  test a string against a machine   */
@@ -322,7 +322,6 @@ REtest(char *str,		/* string to test */
 	m++;
 	RE_CASE();
 
-#ifndef LCOV_UNUSED
     case M_ANY + U_OFF + END_ON:
 	/* NOTREACHED */
 	if (s >= str_end || (s + 1) < str_end) {
@@ -331,7 +330,6 @@ REtest(char *str,		/* string to test */
 	s++;
 	m++;
 	RE_CASE();
-#endif
 
     case M_ANY + U_ON + END_OFF:
 	if (s >= str_end) {
@@ -343,7 +341,6 @@ REtest(char *str,		/* string to test */
 	u_flag = U_OFF;
 	RE_CASE();
 
-#ifndef LCOV_UNUSED
     case M_ANY + U_ON + END_ON:
 	/* NOTREACHED */
 	if (s >= str_end) {
@@ -353,7 +350,6 @@ REtest(char *str,		/* string to test */
 	m++;
 	u_flag = U_OFF;
 	RE_CASE();
-#endif
 
     case M_START + U_OFF + END_OFF:
     case M_START + U_ON + END_OFF:
diff --git a/rexp3.c b/rexp3.c
index 298b87c..0f70cbe 100644
--- a/rexp3.c
+++ b/rexp3.c
@@ -12,7 +12,7 @@ the GNU General Public License, version 2, 1991.
 ********************************************/
 
 /*
- * $MawkId: rexp3.c,v 1.65 2024/08/27 20:48:02 tom Exp $
+ * $MawkId: rexp3.c,v 1.69 2024/12/11 21:45:11 tom Exp $
  */
 
 /*  match a string against a machine   */
@@ -214,9 +214,7 @@ REmatch(char *str,		/* string to test */
 	TR_AT("next");
 	RE_CASE();
 
-#ifndef LCOV_UNUSED
     case M_STR + U_ON + END_ON:
-	/* NOTREACHED */
 	TR_AT("now");
 	if (s >= str_end) {
 	    RE_FILL();
@@ -241,7 +239,6 @@ REmatch(char *str,		/* string to test */
 	u_flag = U_OFF;
 	TR_AT("next");
 	RE_CASE();
-#endif
 
     case M_CLASS + U_OFF + END_OFF:
 	if (s >= str_end) {
@@ -332,10 +329,8 @@ REmatch(char *str,		/* string to test */
 	m++;
 	RE_CASE();
 
-#ifndef LCOV_UNUSED
     case M_ANY + U_OFF + END_ON:
-	/* NOTREACHED */
-	if (s >= str_end) {
+	if ((s >= str_end) || ((s + 1) < str_end)) {
 	    RE_FILL();
 	} else if (!ss) {
 	    if (cb_ss && current_best(s)) {
@@ -347,7 +342,6 @@ REmatch(char *str,		/* string to test */
 	s = str_end;
 	m++;
 	RE_CASE();
-#endif
 
     case M_ANY + U_ON + END_OFF:
 	if (s < str)
@@ -368,9 +362,7 @@ REmatch(char *str,		/* string to test */
 	u_flag = U_OFF;
 	RE_CASE();
 
-#ifndef LCOV_UNUSED
     case M_ANY + U_ON + END_ON:
-	/* NOTREACHED */
 	if (s < str)
 	    s = str;
 	if (s >= str_end) {
@@ -388,7 +380,6 @@ REmatch(char *str,		/* string to test */
 	m++;
 	u_flag = U_OFF;
 	RE_CASE();
-#endif
 
       CASE_UANY(M_START + END_OFF):
 	if (s != str || no_bol) {
diff --git a/test/mawkerrs b/test/mawkerrs
index eb2bebe..5d447f5 100755
--- a/test/mawkerrs
+++ b/test/mawkerrs
@@ -1,5 +1,5 @@
 #!/bin/sh
-# $MawkId: mawkerrs,v 1.19 2024/11/11 23:40:39 tom Exp $
+# $MawkId: mawkerrs,v 1.21 2024/12/11 00:43:22 tom Exp $
 ###############################################################################
 # copyright 2024, Thomas E. Dickey
 #
@@ -245,11 +245,26 @@ echo 'mawk: line 1: illegal reference to variable bar' >$STDERR
 $PROG -Wd 'function foo() { bar = 1; }function bar(){ }BEGIN{ print(); }' 2>&1 | cmp -s - "$STDERR" || Fail "illegal reference to variable"
 Finish "test for illegal reference to variable"
 
+Begin "test for illegal reference to variable NR"
+echo 'mawk: line 1: illegal reference to variable NR' >$STDERR
+$PROG -Wd '{ NR[1] = "alpha"; }' 2>&1 | cmp -s - "$STDERR" || Fail "illegal reference to array ENVIRON"
+Finish "test for illegal reference to variable NR"
+
 Begin "test for illegal reference to array"
 echo 'mawk: line 1: illegal reference to array A' >$STDERR
 $PROG -Wd 'function foo() { A[1] = 1; }function A(){ }BEGIN{ print(); }' 2>&1 | cmp -s - "$STDERR" || Fail "illegal reference to array"
 Finish "test for illegal reference to array"
 
+Begin "test for illegal reference to array ENVIRON"
+echo 'mawk: line 1: illegal reference to array ENVIRON' >$STDERR
+$PROG -Wd '{ ENVIRON = "alpha"; }' 2>&1 | cmp -s - "$STDERR" || Fail "illegal reference to array ENVIRON"
+Finish "test for illegal reference to array ENVIRON"
+
+Begin "test for reference to undefined function"
+echo 'mawk: line 2: function f never defined' >$STDERR
+$PROG -Wd '{ f(z); }' 2>&1 | cmp -s - "$STDERR" || Fail "illegal reference to undefined function"
+Finish "test for reference to undefined function"
+
 ######## print.c
 
 Begin "test sprintf buffer-overflow"