diff --git a/requirements.txt b/requirements.txt
index 70fe253..9b2f270 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,4 +2,5 @@ pyvisa
 visa
 numpy
 xlwt
-matplotlib
\ No newline at end of file
+matplotlib
+fonttools>=4.43.0 # not directly required, pinned by Snyk to avoid a vulnerability
\ No newline at end of file