diff --git a/include/common/regex.h b/include/common/regex.h
index 2f171b3ba..c3b921b3f 100644
--- a/include/common/regex.h
+++ b/include/common/regex.h
@@ -76,7 +76,7 @@ struct hdr_exp {
     void *cond;				/* a possible condition or NULL */
 };
 
-extern regmatch_t pmatch[MAX_MATCH];
+extern THREAD_LOCAL regmatch_t pmatch[MAX_MATCH];
 
 /* "str" is the string that contain the regex to compile.
  * "regex" is preallocated memory. After the execution of this function, this
diff --git a/src/regex.c b/src/regex.c
index 38d7132b3..993a37a43 100644
--- a/src/regex.c
+++ b/src/regex.c
@@ -22,7 +22,7 @@
 #include <proto/log.h>
 
 /* regex trash buffer used by various regex tests */
-regmatch_t pmatch[MAX_MATCH];  /* rm_so, rm_eo for regular expressions */
+THREAD_LOCAL regmatch_t pmatch[MAX_MATCH];  /* rm_so, rm_eo for regular expressions */
 
 int exp_replace(char *dst, unsigned int dst_size, char *src, const char *str, const regmatch_t *matches)
 {