diff --git a/constraints.txt b/constraints.txt
index 0502f54..32d571d 100644
--- a/constraints.txt
+++ b/constraints.txt
@@ -9,7 +9,7 @@ aiohttp>=3.14.0,<4.0.0
 
 # Security-critical indirect dependencies
 # filelock: GHSA-qmgc-5h2g-mvrw (TOCTOU) - fixed in 3.20.3
-filelock>=3.32.5,<4.0.0
+filelock>=4.0.1,<5.0.0
 # virtualenv: GHSA-597g-3phw-6986 (TOCTOU) - fix pending release (>20.36.1)
 # Using latest available until patch is released
 virtualenv>=21.7.16,<22.0.0