From f79cb9007124e387f27a375dec6088d6b67fee6e Mon Sep 17 00:00:00 2001
From: Takashi Kojo <kojo@wolfssl.com>
Date: Fri, 7 Aug 2026 07:18:12 +0900
Subject: [PATCH] Do not free caller's EVP_PKEY until d2i has a replacement

---
 tests/api/test_ossl_pem.c | 28 ++++++++++++++++++++++++++++
 wolfcrypt/src/evp_pk.c    | 10 ++++------
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/tests/api/test_ossl_pem.c b/tests/api/test_ossl_pem.c
index 526cc713c3..89b3b417e7 100644
--- a/tests/api/test_ossl_pem.c
+++ b/tests/api/test_ossl_pem.c
@@ -679,6 +679,34 @@ int test_wolfSSL_PEM_PrivateKey_mldsa(void)
         }
         BIO_free(bio);
         bio = NULL;
+
+        /* A failed read into the same pointer must leave the held key
+         * untouched, not freed (the caller would otherwise be left with
+         * a dangling pointer and a later double free). */
+        {
+            static const char badPem[] =
+                "-----BEGIN PRIVATE KEY-----\n"
+                "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n"
+                "-----END PRIVATE KEY-----\n";
+            static const unsigned char junk[8] =
+                { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 };
+            const unsigned char* jp = junk;
+
+            ExpectNull(wolfSSL_d2i_PrivateKey(WC_EVP_PKEY_DILITHIUM, &pkey,
+                &jp, (long)sizeof(junk)));
+            ExpectNotNull(pkey);
+            ExpectIntEQ(EVP_PKEY_id(pkey), EVP_PKEY_DILITHIUM);
+
+            ExpectNotNull(bio = BIO_new_mem_buf(badPem,
+                (int)sizeof(badPem) - 1));
+            ExpectNull(wolfSSL_PEM_read_bio_PrivateKey(bio, &pkey, NULL,
+                NULL));
+            ExpectNotNull(pkey);
+            ExpectIntEQ(EVP_PKEY_id(pkey), EVP_PKEY_DILITHIUM);
+            BIO_free(bio);
+            bio = NULL;
+        }
+
         EVP_PKEY_free(pkey);
         pkey = NULL;
     }
diff --git a/wolfcrypt/src/evp_pk.c b/wolfcrypt/src/evp_pk.c
index defa3fc756..e70ca24c9f 100644
--- a/wolfcrypt/src/evp_pk.c
+++ b/wolfcrypt/src/evp_pk.c
@@ -1501,12 +1501,8 @@ static WOLFSSL_EVP_PKEY* d2i_evp_pkey(int type, WOLFSSL_EVP_PKEY** out,
         }
     }
 
-    /* Dispose of any WOLFSSL_EVP_PKEY passed in. */
-    if (out != NULL && *out != NULL) {
-        wolfSSL_EVP_PKEY_free(*out);
-        *out = NULL;
-    }
-    /* Create a new WOLFSSL_EVP_PKEY and populate. */
+    /* Create a new WOLFSSL_EVP_PKEY and populate. Any WOLFSSL_EVP_PKEY
+     * passed in is replaced only on success. */
     local = wolfSSL_EVP_PKEY_new();
     if (local == NULL) {
         return NULL;
@@ -1631,6 +1627,8 @@ static WOLFSSL_EVP_PKEY* d2i_evp_pkey(int type, WOLFSSL_EVP_PKEY** out,
             *in += local->pkey_sz;
         }
         if (out != NULL) {
+            /* Dispose of any WOLFSSL_EVP_PKEY passed in. */
+            wolfSSL_EVP_PKEY_free(*out);
             *out = local;
         }
     }