diff --git a/google-auth-library-java/pom.xml b/google-auth-library-java/pom.xml
index 08843c251e35..b34abf40f8db 100644
--- a/google-auth-library-java/pom.xml
+++ b/google-auth-library-java/pom.xml
@@ -81,7 +81,7 @@
     <project.findbugs.version>3.0.2</project.findbugs.version>
     <deploy.autorelease>false</deploy.autorelease>
     <project.error-prone.version>2.48.0</project.error-prone.version>
-    <project.protobuf.version>4.33.2</project.protobuf.version>
+    <project.protobuf.version>4.33.6</project.protobuf.version>
     <project.cel.version>0.9.0-proto3</project.cel.version>
     <project.tink.version>1.15.0</project.tink.version>
     <project.slf4j.version>2.0.17</project.slf4j.version>
diff --git a/grpc-gcp-java/pom.xml b/grpc-gcp-java/pom.xml
index 87ef0c7d4bd6..ab44f5d30a72 100644
--- a/grpc-gcp-java/pom.xml
+++ b/grpc-gcp-java/pom.xml
@@ -68,7 +68,7 @@
     <google-http-client.version>2.2.0</google-http-client.version>
     <gson.version>2.13.2</gson.version>
     <guava.version>33.5.0-jre</guava.version>
-    <protobuf.version>4.33.2</protobuf.version>
+    <protobuf.version>4.33.6</protobuf.version>
     <grpc.version>1.81.0</grpc.version>
     <jsr305.version>3.0.2</jsr305.version>
     <junit.version>4.13.2</junit.version>
diff --git a/librarian.yaml b/librarian.yaml
index 2e577a2901a4..f02c1efe78c7 100644
--- a/librarian.yaml
+++ b/librarian.yaml
@@ -48,7 +48,7 @@ tools:
       version: ""
       local_path: sdk-platform-java/hermetic_build/library_generation
   protoc:
-    version: "33.2"
+    version: "33.6"
     sha256: b24b53f87c151bfd48b112fe4c3a6e6574e5198874f38036aff41df3456b8caf
 default:
   java:
diff --git a/sdk-platform-java/gapic-generator-java-pom-parent/pom.xml b/sdk-platform-java/gapic-generator-java-pom-parent/pom.xml
index dab5526b4e89..477cb748f59d 100644
--- a/sdk-platform-java/gapic-generator-java-pom-parent/pom.xml
+++ b/sdk-platform-java/gapic-generator-java-pom-parent/pom.xml
@@ -31,7 +31,7 @@
     <google.http-client.version>2.2.0</google.http-client.version>
     <gson.version>2.13.2</gson.version>
     <guava.version>33.5.0-jre</guava.version>
-    <protobuf.version>4.33.2</protobuf.version>
+    <protobuf.version>4.33.6</protobuf.version>
     <opentelemetry.version>1.62.0</opentelemetry.version>
     <errorprone.version>2.48.0</errorprone.version>
     <jspecify.version>1.0.0</jspecify.version>