diff --git a/pem_cert/target.c b/pem_cert/target.c
index 916f372..c514fda 100644
--- a/pem_cert/target.c
+++ b/pem_cert/target.c
@@ -25,6 +25,8 @@
 #include <wolfssl/options.h>
 #include <wolfssl/ssl.h>
 
+#define WC_MAX_FUZZ_INPUT_SZ 25000
+
 /* testing wolfSSL_CTX_use_certificate_buffer with PEM as the filetype*/
 
 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t sz)
@@ -32,6 +34,11 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t sz)
     WOLFSSL_CTX *ctx;
     int          ret;
 
+    /* avoid 25s timeout with parsing large files */
+    if (sz > WS_MAX_FUZZ_INPUT_SZ) {
+        return 0;
+    }
+
     wolfSSL_Init();
 
     ctx = wolfSSL_CTX_new(wolfTLSv1_2_server_method());