diff --git a/CHANGES b/CHANGES
index c75e5db7ca..34809457c1 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,4 +1,8 @@
 
+3.1.0-dev.403 | 2020-01-24 15:15:04 -0800
+
+  * Fixed decompose_uri() errors on URIs with empty port component (Frerich Raabe)
+
 3.1.0-dev.398 | 2020-01-23 18:08:43 -0800
 
   * Skip check for outdated docs in Cirrus CI for PRs (Jon Siwek, Corelight)
diff --git a/NEWS b/NEWS
index 772886070f..208fb89d5b 100644
--- a/NEWS
+++ b/NEWS
@@ -67,6 +67,11 @@ Changed Functionality
   previously used. Output from the formatters remains nearly
   identical.
 
+- The ``decompose_uri`` function no longer raises an error when parsing
+  URIs with an empty port number (e.g. ``http://example.org:/``). Instead,
+  the ``portnum`` component of the returned ``URI`` value is left
+  uninitialized.
+
 Removed Functionality
 ---------------------
 
diff --git a/VERSION b/VERSION
index d4ab5411c1..f0fca4b3d7 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-3.1.0-dev.398
+3.1.0-dev.403
diff --git a/scripts/base/utils/urls.zeek b/scripts/base/utils/urls.zeek
index c6ec41cbfc..c8077f5424 100644
--- a/scripts/base/utils/urls.zeek
+++ b/scripts/base/utils/urls.zeek
@@ -119,7 +119,10 @@ function decompose_uri(uri: string): URI
 		# Parse location and port.
 		parts = split_string1(s, /:/);
 		u$netlocation = parts[0];
-		u$portnum = to_count(parts[1]);
+		if ( parts[1] != "" )
+		    {
+		    u$portnum = to_count(parts[1]);
+		    }
 		}
 	else
 		{
diff --git a/testing/btest/Baseline/scripts.base.utils.urls/output b/testing/btest/Baseline/scripts.base.utils.urls/output
index 2d8f5b2c4d..e10010ab10 100644
--- a/testing/btest/Baseline/scripts.base.utils.urls/output
+++ b/testing/btest/Baseline/scripts.base.utils.urls/output
@@ -6,6 +6,7 @@
 [scheme=http, netlocation=hyphen-example.com, portnum=<uninitialized>, path=/index.asp, file_name=index.asp, file_base=index, file_ext=asp, params={
 [q] = 123
 }]
+[scheme=git, netlocation=git.kernel.org, portnum=<uninitialized>, path=/pub/scm/linux/, file_name=<uninitialized>, file_base=<uninitialized>, file_ext=<uninitialized>, params=<uninitialized>]
 [scheme=<uninitialized>, netlocation=dfasjdfasdfasdf, portnum=<uninitialized>, path=/, file_name=<uninitialized>, file_base=<uninitialized>, file_ext=<uninitialized>, params={
 
 }]
diff --git a/testing/btest/scripts/base/utils/urls.test b/testing/btest/scripts/base/utils/urls.test
index 666f805edb..c307ee601e 100644
--- a/testing/btest/scripts/base/utils/urls.test
+++ b/testing/btest/scripts/base/utils/urls.test
@@ -8,6 +8,7 @@ print decompose_uri("https://www.example.com/");
 print decompose_uri("http://example.com:99/test//?foo=bar");
 print decompose_uri("ftp://1.2.3.4/pub/files/something.exe");
 print decompose_uri("http://hyphen-example.com/index.asp?q=123");
+print decompose_uri("git://git.kernel.org:/pub/scm/linux/");
 
 # This is mostly undefined behavior but it doesn't give any 
 # reporter messages at least.