diff --git a/src/libstrongswan/plugins/botan/botan_aead.c b/src/libstrongswan/plugins/botan/botan_aead.c
index 2182a047c..43bf1bbe0 100644
--- a/src/libstrongswan/plugins/botan/botan_aead.c
+++ b/src/libstrongswan/plugins/botan/botan_aead.c
@@ -164,6 +164,7 @@ METHOD(aead_t, decrypt, bool,
 	chunk_t *plain)
 {
 	u_char *out;
+	bool valid;
 
 	if (encrypted.len < this->icv_size)
 	{
@@ -177,8 +178,13 @@ METHOD(aead_t, decrypt, bool,
 		*plain = chunk_alloc(encrypted.len);
 		out = plain->ptr;
 	}
-	return do_crypt(this, encrypted, assoc, iv, out,
-					BOTAN_CIPHER_INIT_FLAG_DECRYPT);
+	valid = do_crypt(this, encrypted, assoc, iv, out,
+					 BOTAN_CIPHER_INIT_FLAG_DECRYPT);
+	if (!valid && plain)
+	{
+		chunk_free(plain);
+	}
+	return valid;
 }
 
 METHOD(aead_t, get_block_size, size_t,