diff --git a/src/x509.c b/src/x509.c
index ff411069a6..5b24c1bb78 100644
--- a/src/x509.c
+++ b/src/x509.c
@@ -12897,6 +12897,16 @@ cleanup:
                 XFREE(mldsa, x509->heap, DYNAMIC_TYPE_MLDSA);
                 return WOLFSSL_FATAL_ERROR;
             }
+            /* sigType above came from the cached pkey->mldsaOID; require
+             * the decoded key to agree so a stale cache cannot emit a
+             * certificate whose signatureAlgorithm disagrees with the
+             * actual signature. */
+            if (oidSum != WOLFSSL_ATOMIC_LOAD(pkey->mldsaOID)) {
+                WOLFSSL_MSG("ML-DSA key does not match cached pkey OID");
+                wc_MlDsaKey_Free(mldsa);
+                XFREE(mldsa, x509->heap, DYNAMIC_TYPE_MLDSA);
+                return WOLFSSL_FATAL_ERROR;
+            }
             switch (oidSum) {
                 case ML_DSA_44k:
                     type = ML_DSA_44_TYPE;
diff --git a/tests/api/test_ossl_x509_pk.c b/tests/api/test_ossl_x509_pk.c
index 468123ff85..84de675afb 100644
--- a/tests/api/test_ossl_x509_pk.c
+++ b/tests/api/test_ossl_x509_pk.c
@@ -425,6 +425,19 @@ int test_wolfSSL_X509_set_pubkey(void)
                         WOLFSSL_SUCCESS);
                     wolfSSL_EVP_PKEY_free(pubkey);
                     pubkey = NULL;
+
+                    /* A stale/tampered mldsaOID cache must fail the sign
+                     * rather than emit a certificate whose
+                     * signatureAlgorithm disagrees with the actual key. */
+                    if (EXPECT_SUCCESS() && pkey != NULL) {
+                        int realOID = WOLFSSL_ATOMIC_LOAD(pkey->mldsaOID);
+                        int wrongOID = (realOID == ML_DSA_44k) ?
+                            ML_DSA_65k : ML_DSA_44k;
+                        WOLFSSL_ATOMIC_STORE(pkey->mldsaOID, wrongOID);
+                        ExpectIntEQ(wolfSSL_X509_sign(x509, pkey, NULL),
+                            WC_NO_ERR_TRACE(WOLFSSL_FAILURE));
+                        WOLFSSL_ATOMIC_STORE(pkey->mldsaOID, realOID);
+                    }
                 }
             #endif
                 if (ki + 1 < sizeof(keyFiles) / sizeof(keyFiles[0])) {