diff --git a/src/libsodium/crypto_aead/aegis256/aesni/aead_aegis256_aesni.c b/src/libsodium/crypto_aead/aegis256/aesni/aead_aegis256_aesni.c
index d7b208a6..a9bd18db 100644
--- a/src/libsodium/crypto_aead/aegis256/aesni/aead_aegis256_aesni.c
+++ b/src/libsodium/crypto_aead/aegis256/aesni/aead_aegis256_aesni.c
@@ -221,14 +221,22 @@ crypto_aead_aegis256_decrypt_detached(unsigned char *m, unsigned char *nsec, con
         memcpy(src, ad + i, adlen & 0xf);
         crypto_aead_aegis256_enc(dst, src, state);
     }
-    for (i = 0ULL; i + 16ULL <= mlen; i += 16ULL) {
-        crypto_aead_aegis256_dec(m + i, c + i, state);
+    if (m != NULL) {
+        for (i = 0ULL; i + 16ULL <= mlen; i += 16ULL) {
+            crypto_aead_aegis256_dec(m + i, c + i, state);
+        }
+    } else {
+        for (i = 0ULL; i + 16ULL <= mlen; i += 16ULL) {
+            crypto_aead_aegis256_dec(dst, c + i, state);
+        }
     }
     if (mlen & 0xf) {
         memset(src, 0, 16);
         memcpy(src, c + i, mlen & 0xf);
         crypto_aead_aegis256_dec(dst, src, state);
-        memcpy(m + i, dst, mlen & 0xf);
+        if (m != NULL) {
+            memcpy(m + i, dst, mlen & 0xf);
+        }
         memset(dst, 0, mlen & 0xf);
         state[0] = _mm_xor_si128(state[0], _mm_loadu_si128((__m128i *) dst));
     }
diff --git a/test/default/aead_aegis256.c b/test/default/aead_aegis256.c
index 582a2dc1..49ef1317 100644
--- a/test/default/aead_aegis256.c
+++ b/test/default/aead_aegis256.c
@@ -2144,6 +2144,11 @@ tv(void)
             printf("Verification of test vector #%u with a truncated tag failed\n",
                    (unsigned int) i);
         }
+        if (i == 0 && crypto_aead_aegis256_decrypt(NULL, NULL,
+                                                   NULL, ciphertext, ciphertext_len,
+                                                   ad, ad_len, nonce, key) != 0) {
+            printf("Verification of test vector #%u's tag failed\n", (unsigned int) i);
+        }
         if (crypto_aead_aegis256_decrypt(decrypted, &found_message_len, NULL, ciphertext,
                                          ciphertext_len, ad, ad_len, nonce, key) != 0) {
             printf("Verification of test vector #%u failed\n", (unsigned int) i);