diff --git a/debian/libwsutil0.symbols b/debian/libwsutil0.symbols
index c11a8294ad..7da55031ff 100644
--- a/debian/libwsutil0.symbols
+++ b/debian/libwsutil0.symbols
@@ -424,6 +424,7 @@ libwsutil.so.0 libwsutil0 #MINVER#
  ws_regex_compile@Base 3.7.0
  ws_regex_free@Base 3.7.0
  ws_regex_matches@Base 3.7.0
+ ws_regex_matches_length@Base 3.7.0
  ws_regex_pattern@Base 3.7.0
  ws_socket_ptoa@Base 3.1.1
  ws_strcasestr@Base 3.7.0
diff --git a/epan/ftypes/ftype-bytes.c b/epan/ftypes/ftype-bytes.c
index 12c703b185..f03167e852 100644
--- a/epan/ftypes/ftype-bytes.c
+++ b/epan/ftypes/ftype-bytes.c
@@ -558,7 +558,7 @@ cmp_matches(const fvalue_t *fv, const ws_regex_t *regex)
 {
 	GByteArray *a = fv->value.bytes;
 
-	return ws_regex_matches(regex, a->data, a->len);
+	return ws_regex_matches_length(regex, a->data, a->len);
 }
 
 void
diff --git a/epan/ftypes/ftype-protocol.c b/epan/ftypes/ftype-protocol.c
index b50b52ef03..dba821d7d6 100644
--- a/epan/ftypes/ftype-protocol.c
+++ b/epan/ftypes/ftype-protocol.c
@@ -291,9 +291,9 @@ cmp_matches(const fvalue_t *fv, const ws_regex_t *regex)
 		if (a->tvb != NULL) {
 			tvb_len = tvb_captured_length(a->tvb);
 			data = (const char *)tvb_get_ptr(a->tvb, 0, tvb_len);
-			rc = ws_regex_matches(regex, data, tvb_len);
+			rc = ws_regex_matches_length(regex, data, tvb_len);
 		} else {
-			rc = ws_regex_matches(regex, a->proto_string, WS_REGEX_ZERO_TERMINATED);
+			rc = ws_regex_matches(regex, a->proto_string);
 		}
 	}
 	CATCH_ALL {
diff --git a/epan/ftypes/ftype-string.c b/epan/ftypes/ftype-string.c
index 133f5a9b38..606cdd0194 100644
--- a/epan/ftypes/ftype-string.c
+++ b/epan/ftypes/ftype-string.c
@@ -152,7 +152,7 @@ cmp_matches(const fvalue_t *fv, const ws_regex_t *regex)
 	if (! regex) {
 		return FALSE;
 	}
-	return ws_regex_matches(regex, str, WS_REGEX_ZERO_TERMINATED);
+	return ws_regex_matches(regex, str);
 }
 
 void
diff --git a/wsutil/regex.c b/wsutil/regex.c
index 0698df9161..bb3bd0b3de 100644
--- a/wsutil/regex.c
+++ b/wsutil/regex.c
@@ -83,20 +83,17 @@ ws_regex_compile(const char *patt, char **errmsg)
 
 
 static bool
-match_pcre2(pcre2_code *code, const char *subj, size_t subj_size)
+match_pcre2(pcre2_code *code, PCRE2_SPTR subject, PCRE2_SIZE length)
 {
-    PCRE2_SIZE length;
     pcre2_match_data *match_data;
     int rc;
 
-    length = subj_size == WS_REGEX_ZERO_TERMINATED ? PCRE2_ZERO_TERMINATED : (PCRE2_SIZE)subj_size;
-
     /* We don't use the matched substring but pcre2_match requires
      * at least one pair of offsets. */
     match_data = pcre2_match_data_create(1, NULL);
 
     rc = pcre2_match(code,
-                    subj,
+                    subject,
                     length,
                     0,          /* start at offset zero of the subject */
                     0,          /* default options */
@@ -123,12 +120,23 @@ match_pcre2(pcre2_code *code, const char *subj, size_t subj_size)
 
 
 bool
-ws_regex_matches(const ws_regex_t *re, const char *subj, size_t subj_size)
+ws_regex_matches(const ws_regex_t *re, const char *subj)
 {
     ws_return_val_if_null(re, FALSE);
     ws_return_val_if_null(subj, FALSE);
 
-    return match_pcre2(re->code, subj, subj_size);
+    return match_pcre2(re->code, (PCRE2_SPTR)subj, PCRE2_ZERO_TERMINATED);
+}
+
+
+bool
+ws_regex_matches_length(const ws_regex_t *re,
+                        const char *subj, size_t subj_length)
+{
+    ws_return_val_if_null(re, FALSE);
+    ws_return_val_if_null(subj, FALSE);
+
+    return match_pcre2(re->code, (PCRE2_SPTR)subj, (PCRE2_SIZE)subj_length);
 }
 
 
diff --git a/wsutil/regex.h b/wsutil/regex.h
index eec51b7baf..df38ecae32 100644
--- a/wsutil/regex.h
+++ b/wsutil/regex.h
@@ -12,8 +12,6 @@
 
 #include <wireshark.h>
 
-#define WS_REGEX_ZERO_TERMINATED SIZE_MAX
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -24,8 +22,14 @@ typedef struct _ws_regex ws_regex_t;
 WS_DLL_PUBLIC ws_regex_t *
 ws_regex_compile(const char *patt, char **errmsg);
 
+/** Matches a null-terminated subject string. */
 WS_DLL_PUBLIC bool
-ws_regex_matches(const ws_regex_t *re, const char *subj, size_t subj_size);
+ws_regex_matches(const ws_regex_t *re, const char *subj);
+
+/** Matches a subject string length in 8 bit code units. */
+WS_DLL_PUBLIC bool
+ws_regex_matches_length(const ws_regex_t *re,
+                        const char *subj, size_t subj_length);
 
 WS_DLL_PUBLIC void
 ws_regex_free(ws_regex_t *re);