diff --git a/.clusterfuzzlite/Dockerfile b/.clusterfuzzlite/Dockerfile
index f979cdfe..316c26ea 100644
--- a/.clusterfuzzlite/Dockerfile
+++ b/.clusterfuzzlite/Dockerfile
@@ -1,4 +1,6 @@
 FROM gcr.io/oss-fuzz-base/base-builder:v1
+
+ENV CLUSTERFUZZLITE=TRUE
 RUN apt-get update && apt-get install -y bison libssl-dev libevent-dev libsystemd-dev
 COPY . $SRC/openiked-portable
 WORKDIR openiked-portable
diff --git a/CMakeLists.txt b/CMakeLists.txt
index cd6cc3f2..95c4e3fe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -404,7 +404,7 @@ endif()
 if(CLUSTERFUZZ)
 	message("Compiling parser-libfuzzer")
 	add_subdirectory(regress/parser-libfuzzer)
-	if (NOT DEFINED ENV{CC} OR NOT DEFINED ENV{CFLAGS})
+	if (NOT DEFINED ENV{CLUSTERFUZZLITE})
 		set(CMAKE_C_COMPILER clang)
 		string(APPEND CMAKE_C_FLAGS " -g -O1 -fsanitize=fuzzer-no-link")
 	endif()
diff --git a/iked/CMakeLists.txt b/iked/CMakeLists.txt
index 3de5e8fb..685f19d2 100644
--- a/iked/CMakeLists.txt
+++ b/iked/CMakeLists.txt
@@ -112,7 +112,7 @@ endif()
 target_include_directories(iked PRIVATE ${INC_DIRS})
 target_include_directories(iked-shared PRIVATE ${INC_DIRS})
 
-if(CLUSTERFUZZ AND DEFINED ENV{CC} AND DEFINED ENV{CFLAGS})
+if(DEFINED ENV{CLUSTERFUZZLITE})
 	target_link_libraries(iked-shared
         	"-lm -Wl,-Bstatic -lssl -lcrypto -levent -Wl,-Bdynamic" compat
 	)
diff --git a/iked/ikev2_pld.c b/iked/ikev2_pld.c
index b729d68f..05ed27a0 100644
--- a/iked/ikev2_pld.c
+++ b/iked/ikev2_pld.c
@@ -853,9 +853,6 @@ ikev2_pld_cert(struct iked *env, struct ikev2_payload *pld,
 		}
 	}
 
-	if (certid->id_buf) {
-		ibuf_free(certid->id_buf);
-	}
 	if ((certid->id_buf = ibuf_new(buf, len)) == NULL) {
 		log_debug("%s: failed to save cert", __func__);
 		return (-1);
diff --git a/regress/parser-libfuzzer/CMakeLists.txt b/regress/parser-libfuzzer/CMakeLists.txt
index 0e267952..a964d83f 100644
--- a/regress/parser-libfuzzer/CMakeLists.txt
+++ b/regress/parser-libfuzzer/CMakeLists.txt
@@ -28,7 +28,7 @@ target_include_directories(test_libfuzzer
 )
 
 # when using clusterfuzz we need static linking and clusterfuzz' compiler arguments
-if (DEFINED ENV{CC} AND DEFINED ENV{CFLAGS})
+if (DEFINED ENV{CLUSTERFUZZLITE})
 	target_link_libraries(test_libfuzzer
 		"-lm -Wl,-Bstatic -lssl -lcrypto -levent" compat iked-shared $ENV{LIB_FUZZING_ENGINE}
 	)