diff --git a/lib/noproxy.c b/lib/noproxy.c
index b9e8492fd6..1e19c369c0 100644
--- a/lib/noproxy.c
+++ b/lib/noproxy.c
@@ -166,9 +166,12 @@ static bool match_ip(int type, const char *token, size_t tokenlen,
   slash = strchr(check, '/');
   /* if the slash is part of this token, use it */
   if(slash) {
-    /* if the bits variable gets a crazy value here, that is fine as
-       the value will then be rejected in the cidr function */
-    bits = (unsigned int)atoi(slash + 1);
+    curl_off_t value;
+    const char *p = &slash[1];
+    if(curlx_str_number(&p, &value, 128) || *p)
+      return FALSE;
+    /* a too large value is rejected in the cidr function below */
+    bits = (unsigned int)value;
     *slash = 0; /* null-terminate there */
   }
   if(type == TYPE_IPV6)
diff --git a/tests/data/test1614 b/tests/data/test1614
index 504d328fc6..8e8f6b3f4d 100644
--- a/tests/data/test1614
+++ b/tests/data/test1614
@@ -2,6 +2,7 @@
 <info>
 <keywords>
 unittest
+noproxy
 </keywords>
 </info>
 
diff --git a/tests/unit/unit1614.c b/tests/unit/unit1614.c
index 9ba5f95ebb..10140ee602 100644
--- a/tests/unit/unit1614.c
+++ b/tests/unit/unit1614.c
@@ -99,8 +99,14 @@ static CURLcode test_unit1614(const char *arg)
     { "foobar", "foobar", TRUE},
     { "192.168.0.1", "foobar", FALSE},
     { "192.168.0.1", "192.168.0.0/16", TRUE},
+    { "192.168.0.1", "192.168.0.0/16a", FALSE},
+    { "192.168.0.1", "192.168.0.0/16 ", TRUE},
+    { "192.168.0.1", "192.168.0.0/a16", FALSE},
+    { "192.168.0.1", "192.168.0.0/ 16", FALSE},
     { "192.168.0.1", "192.168.0.0/24", TRUE},
     { "192.168.0.1", "192.168.0.0/32", FALSE},
+    { "192.168.0.1", "192.168.0.1/32", TRUE},
+    { "192.168.0.1", "192.168.0.1/33", FALSE},
     { "192.168.0.1", "192.168.0.0", FALSE},
     { "192.168.1.1", "192.168.0.0/24", FALSE},
     { "192.168.1.1", "192.168.0.0/33", FALSE},
@@ -111,7 +117,13 @@ static CURLcode test_unit1614(const char *arg)
     { "[::1]", "foo, bar, ::1/64", TRUE},
     { "[::1]", "::1/64", TRUE},
     { "[::1]", "::1/96", TRUE},
+    { "[::1]", "::1/129", FALSE},
+    { "[::1]", "::1/128", TRUE},
     { "[::1]", "::1/127", TRUE},
+    { "[::1]", "::1/a127", FALSE},
+    { "[::1]", "::1/127a", FALSE},
+    { "[::1]", "::1/ 127", FALSE},
+    { "[::1]", "::1/127 ", TRUE},
     { "[::1]", "::1/126", TRUE},
     { "[::1]", "::1/125", TRUE},
     { "[::1]", "::1/124", TRUE},