diff --git a/lib/http.c b/lib/http.c
index 9af3a70514..6fdaa2e434 100644
--- a/lib/http.c
+++ b/lib/http.c
@@ -1440,6 +1440,10 @@ bool Curl_compareheader(const char *headerline, /* line to check */
       do
         curlx_str_passblanks(&p);
       while(!curlx_str_single(&p, ','));
+      /* trailing blanks may move the parsing point past the value end,
+         then there is nothing left to match */
+      if((size_t)(p - o) > len)
+        break;
       len -= (p - o);
     }
   }
diff --git a/tests/data/test1625 b/tests/data/test1625
index 58d661c385..c717933b30 100644
--- a/tests/data/test1625
+++ b/tests/data/test1625
@@ -19,7 +19,7 @@ Curl_compareheader unit test
 
 <verify>
 <stdout mode="text">
-31 invokes
+33 invokes
 </stdout>
 </verify>
 </testcase>
diff --git a/tests/unit/unit1625.c b/tests/unit/unit1625.c
index 370b65a4fa..491b553954 100644
--- a/tests/unit/unit1625.c
+++ b/tests/unit/unit1625.c
@@ -102,6 +102,11 @@ static CURLcode test_unit1625(const char *arg)
     { "Encoding: super-nice", "Encoding:", "super-nice", TRUE },
     /* hyphenated second token */
     { "Encoding: extra-good, super-nice", "Encoding:", "super-nice", TRUE },
+    /* trailing blanks after the last comma */
+    { "Encoding: gzipped,  ", "Encoding:", "gzip", FALSE },
+    /* the scan must not cross into a second line */
+    { "Encoding: gzipped,  \r\nEncoding: gzip, chunked", "Encoding:",
+      "chunked", FALSE },
   };
 
   for(i = 0; i < CURL_ARRAYSIZE(list); i++) {