diff --git a/NEWS b/NEWS
index 575fcdbbad9..a1dcf7c15d6 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,7 @@ PHP                                                                        NEWS
 
 - Core:
   . Fix OSS-Fuzz #447521098 (Fatal error during sccp shift eval). (ilutov)
+  . Fixed bug GH-20002 (Broken build on *BSD with MSAN). (outtersg)
 
 - BcMath:
   . Fixed bug GH-20006 (Power of 0 of BcMath number causes UB). (nielsdos)
diff --git a/Zend/zend_string.c b/Zend/zend_string.c
index c864a847af3..7291672b6b8 100644
--- a/Zend/zend_string.c
+++ b/Zend/zend_string.c
@@ -500,8 +500,10 @@ ZEND_API zend_string *zend_string_concat3(
 	return res;
 }
 
-/* strlcpy and strlcat are not intercepted by msan, so we need to do it ourselves. */
-#if __has_feature(memory_sanitizer)
+/* strlcpy and strlcat are not always intercepted by msan, so we need to do it
+ * ourselves. Apply a simple heuristic to determine the platforms that need it.
+ * See https://github.com/php/php-src/issues/20002. */
+#if __has_feature(memory_sanitizer) && !defined(__FreeBSD__) && !defined(__NetBSD__) && !defined(__APPLE__)
 static size_t (*libc_strlcpy)(char *__restrict, const char *__restrict, size_t);
 size_t strlcpy(char *__restrict dest, const char *__restrict src, size_t n)
 {