diff --git a/LENR_Math_Sim/backend/requirements.txt b/LENR_Math_Sim/backend/requirements.txt
index 1e35bcb..c972263 100644
--- a/LENR_Math_Sim/backend/requirements.txt
+++ b/LENR_Math_Sim/backend/requirements.txt
@@ -39,7 +39,7 @@ pytest-cov==4.1.0
 hypothesis==6.92.2  # Property-based testing
 
 # Development Tools
-black==24.10.0  # Updated for ReDoS vulnerability fix
+black==26.3.1  # Updated for CVE-2026-32274 arbitrary file-write fix
 ruff==0.1.11
 mypy==1.8.0
 ipython==8.19.0