diff --git a/lib/libc/include/libc_private.h b/lib/libc/include/libc_private.h
--- a/lib/libc/include/libc_private.h
+++ b/lib/libc/include/libc_private.h
@@ -374,5 +374,7 @@
 struct _xlocale;
 struct __nl_cat_d *__catopen_l(const char *name, int type,
 	    struct _xlocale *locale);
+int __strerror_rl(int errnum, char *strerrbuf, size_t buflen,
+	    struct _xlocale *locale);
 
 #endif /* _LIBC_PRIVATE_H_ */
diff --git a/lib/libc/stdio/vfprintf.c b/lib/libc/stdio/vfprintf.c
--- a/lib/libc/stdio/vfprintf.c
+++ b/lib/libc/stdio/vfprintf.c
@@ -312,6 +312,8 @@
 	int width;		/* width from format (%8d), or 0 */
 	int prec;		/* precision from format; <0 for N/A */
 	int saved_errno;
+	int error;
+	char errnomsg[NL_TEXTMAX];
 	char sign;		/* sign prefix (' ', '+', '-', or \0) */
 	struct grouping_state gs; /* thousands' grouping info */
 
@@ -829,7 +831,9 @@
 			break;
 #endif /* !NO_FLOATING_POINT */
 		case 'm':
-			cp = strerror(saved_errno);
+			error = strerror_rl(saved_errno, errnomsg,
+			    sizeof(errnomsg), locale);
+			cp = error == 0 ? errnomsg : "<strerror failure>";
 			size = (prec >= 0) ? strnlen(cp, prec) : strlen(cp);
 			sign = '\0';
 			break;
diff --git a/lib/libc/stdio/xprintf_errno.c b/lib/libc/stdio/xprintf_errno.c
--- a/lib/libc/stdio/xprintf_errno.c
+++ b/lib/libc/stdio/xprintf_errno.c
@@ -38,7 +38,8 @@
 #include "printf.h"
 
 int
-__printf_arginfo_errno(const struct printf_info *pi __unused, size_t n, int *argt)
+__printf_arginfo_errno(const struct printf_info *pi __unused, size_t n,
+    int *argt)
 {
 
 	assert(n >= 1);
@@ -47,17 +48,19 @@
 }
 
 int
-__printf_render_errno(struct __printf_io *io, const struct printf_info *pi __unused, const void *const *arg)
+__printf_render_errno(struct __printf_io *io, const struct printf_info *pi
+    __unused, const void *const *arg)
 {
 	int ret, error;
 	char buf[64];
+	char errnomsg[NL_TEXTMAX];
 	const char *p;
 
 	ret = 0;
 	error = *((const int *)arg[0]);
 	if (error >= 0 && error < __hidden_sys_nerr) {
-		p = strerror(error);
-		return (__printf_out(io, pi, p, strlen(p)));
+		strerror_r(error, errnomsg, sizeof(errnomsg));
+		return (__printf_out(io, pi, errnomsg, strlen(errnomsg)));
 	}
 	sprintf(buf, "errno=%d/0x%x", error, error);
 	ret += __printf_out(io, pi, buf, strlen(buf));
diff --git a/lib/libc/string/strerror.c b/lib/libc/string/strerror.c
--- a/lib/libc/string/strerror.c
+++ b/lib/libc/string/strerror.c
@@ -74,8 +74,8 @@
 	strlcat(buf, t, len);
 }
 
-static int
-strerror_rl(int errnum, char *strerrbuf, size_t buflen, locale_t locale)
+int
+__strerror_rl(int errnum, char *strerrbuf, size_t buflen, locale_t locale)
 {
 	int retval = 0;
 #if defined(NLS)
@@ -116,7 +116,7 @@
 int
 strerror_r(int errnum, char *strerrbuf, size_t buflen)
 {
-	return (strerror_rl(errnum, strerrbuf, buflen, __get_locale()));
+	return (__strerror_rl(errnum, strerrbuf, buflen, __get_locale()));
 }
 
 char *
@@ -124,7 +124,7 @@
 {
 	static _Thread_local char ebuf[NL_TEXTMAX];
 
-	if (strerror_rl(num, ebuf, sizeof(ebuf), locale) != 0)
+	if (__strerror_rl(num, ebuf, sizeof(ebuf), locale) != 0)
 		errno = EINVAL;
 	return (ebuf);
 }
@@ -134,7 +134,7 @@
 {
 	static char ebuf[NL_TEXTMAX];
 
-	if (strerror_rl(num, ebuf, sizeof(ebuf), __get_locale()) != 0)
+	if (__strerror_rl(num, ebuf, sizeof(ebuf), __get_locale()) != 0)
 		errno = EINVAL;
 	return (ebuf);
 }