diff --git a/contract-tests/images/mock-collector/pyproject.toml b/contract-tests/images/mock-collector/pyproject.toml
index 42e13c868..3b7b76396 100644
--- a/contract-tests/images/mock-collector/pyproject.toml
+++ b/contract-tests/images/mock-collector/pyproject.toml
@@ -13,7 +13,7 @@ dependencies = [
     "grpcio ~= 1.66.0",
     "opentelemetry-proto==1.33.1",
     "opentelemetry-sdk==1.33.1",
-    "protobuf==5.26.1",
+    "protobuf==5.29.5",
     "typing-extensions==4.12.2"
 ]
 
diff --git a/contract-tests/images/mock-collector/requirements.txt b/contract-tests/images/mock-collector/requirements.txt
index 12e69148b..923722d77 100644
--- a/contract-tests/images/mock-collector/requirements.txt
+++ b/contract-tests/images/mock-collector/requirements.txt
@@ -1,5 +1,5 @@
 grpcio==1.66.2
 opentelemetry-proto==1.33.1
 opentelemetry-sdk==1.33.1
-protobuf==5.26.1
+protobuf==5.29.5
 typing-extensions==4.12.2