diff --git a/providers/implementations/encode_decode/encode_key2text.c b/providers/implementations/encode_decode/encode_key2text.c
index f8f9712e96..9455f97c4a 100644
--- a/providers/implementations/encode_decode/encode_key2text.c
+++ b/providers/implementations/encode_decode/encode_key2text.c
@@ -80,6 +80,9 @@ static int print_labeled_bignum(BIO *out, const char *label, const BIGNUM *bn)
     }
 
     hex_str = BN_bn2hex(bn);
+    if (hex_str == NULL)
+        return 0;
+
     p = hex_str;
     if (*p == '-') {
         ++p;