diff --git a/requirements/default.txt b/requirements/default.txt
index ca16bb5b1..ec8d8ceb7 100644
--- a/requirements/default.txt
+++ b/requirements/default.txt
@@ -204,7 +204,8 @@ requests-hawk==1.0.0 \
     --hash=sha256:c2626ab31ebef0c81b97781c44c2275bfcc6d8e8520fc4ced495f0f386f8fe26
 requests-mock==1.5.2 \
     --hash=sha256:8ca0628dc66d3f212878932fd741b02aa197ad53fd2228164800a169a4a826af \
-    --hash=sha256:7a5fa99db5e3a2a961b6f20ed40ee6baeff73503cf0a553cc4d679409e6170fb
+    --hash=sha256:7a5fa99db5e3a2a961b6f20ed40ee6baeff73503cf0a553cc4d679409e6170fb \
+    # Pinning urllib3 >=1.21.1,<1.25
 sort-requirements==1.3.0 \
     --hash=sha256:56de1172f5656aa9a0dfb7575913fff3d9ab80090e6bd4095fd6feec312c7d7c \
     --hash=sha256:8038315f8932b1496567f1241ea482aa900845d5a5116c7d23835e783a3a2082