diff --git a/src/libstrongswan/plugins/curl/curl_fetcher.c b/src/libstrongswan/plugins/curl/curl_fetcher.c
index a8cca98da..644f27709 100644
--- a/src/libstrongswan/plugins/curl/curl_fetcher.c
+++ b/src/libstrongswan/plugins/curl/curl_fetcher.c
@@ -80,7 +80,7 @@ static size_t curl_cb(void *ptr, size_t size, size_t nmemb, cb_data_t *data)
 METHOD(fetcher_t, fetch, status_t,
 	private_curl_fetcher_t *this, char *uri, void *userdata)
 {
-	char error[CURL_ERROR_SIZE];
+	char error[CURL_ERROR_SIZE], *enc_uri;
 	status_t status;
 	cb_data_t data = {
 		.cb = this->cb,
@@ -92,9 +92,14 @@ METHOD(fetcher_t, fetch, status_t,
 		*(chunk_t*)userdata = chunk_empty;
 	}
 
-	if (curl_easy_setopt(this->curl, CURLOPT_URL, uri) != CURLE_OK)
+	/* the URI has to be URL-encoded, we only replace spaces as replacing other
+	 * characters (e.g. '/' or ':') would render the URI invalid */
+	enc_uri = strreplace(uri, " ", "%20");
+
+	if (curl_easy_setopt(this->curl, CURLOPT_URL, enc_uri) != CURLE_OK)
 	{	/* URL type not supported by curl */
-		return NOT_SUPPORTED;
+		status = NOT_SUPPORTED;
+		goto out;
 	}
 	curl_easy_setopt(this->curl, CURLOPT_ERRORBUFFER, error);
 	curl_easy_setopt(this->curl, CURLOPT_FAILONERROR, TRUE);
@@ -125,6 +130,12 @@ METHOD(fetcher_t, fetch, status_t,
 			status = FAILED;
 			break;
 	}
+
+out:
+	if (enc_uri != uri)
+	{
+		free(enc_uri);
+	}
 	return status;
 }