diff --git a/API-CHANGELOG.md b/API-CHANGELOG.md
index 6f75b3a880..d521f9c024 100644
--- a/API-CHANGELOG.md
+++ b/API-CHANGELOG.md
@@ -56,6 +56,7 @@ This section contains changes targeting a future version.
 - Fixed a bug in `Forwarded` HTTP header parsing where the extracted IP address could be incorrect when no comma or semicolon delimiter follows the address. This could cause the server to misidentify a client's IP address when operating behind a reverse proxy. [#6529](https://github.com/XRPLF/rippled/pull/6529)
 - `vault_info`: Errors now identify what the request got wrong instead of reporting every failure as the unregistered token `malformedRequest`, and the `error`, `error_code` and `error_message` fields now agree with each other. An invalid `vault_id` or `seq` returns `invalidParams`, an invalid `owner` returns `actMalformed`, and a request that mixes `vault_id` with `owner`/`seq` or supplies neither returns `invalidParams` with a message naming the accepted combinations. [#8015](https://github.com/XRPLF/rippled/pull/8015)
 - `vault_info`: A well-formed all-zero `vault_id` now returns `entryNotFound` instead of being rejected as malformed, and `entryNotFound` responses now include `error_code` and `error_message`. Clients that request `ripplerpc` 3.0 or above therefore receive HTTP 400 with that error rather than HTTP 200. [#8015](https://github.com/XRPLF/rippled/pull/8015)
+- `vault_info`: `vault_id` and `owner` must now be strings, matching how `ledger_entry` reads the same fields. An object or an array in either field previously produced an internal error, and a number was silently converted to its decimal text; `vault_id` now returns `invalidParams` and `owner` returns `actMalformed`. [#8015](https://github.com/XRPLF/rippled/pull/8015)
 - `gateway_balances`: The `account` and `ident` fields now return an `invalidParams` error if the value is not a string, instead of an `internal` error. [#7655](https://github.com/XRPLF/rippled/pull/7655)
 - `account_lines`: The `peer` field now returns an error if the value is not a string. [#7728](https://github.com/XRPLF/rippled/pull/7728)
 
diff --git a/src/test/app/Vault_test.cpp b/src/test/app/Vault_test.cpp
index cb87442850..bad2d62323 100644
--- a/src/test/app/Vault_test.cpp
+++ b/src/test/app/Vault_test.cpp
@@ -5464,21 +5464,47 @@ class Vault_test : public beast::unit_test::Suite
         }
 
         {
-            testcase("RPC vault_info json zero vault_id");
+            testcase("RPC vault_info json numeric vault_id");
             json::Value jvParams;
             jvParams[jss::ledger_index] = jss::validated;
             jvParams[jss::vault_id] = 0;
             auto jv = env.rpc("json", "vault_info", to_string(jvParams));
+            checkError(
+                jv[jss::result],
+                "invalidParams",
+                RpcInvalidParams,
+                "Invalid field 'vault_id', not hex string.");
+        }
+
+        {
+            testcase("RPC vault_info json object vault_id");
+            json::Value jvParams;
+            jvParams[jss::ledger_index] = jss::validated;
+            jvParams[jss::vault_id] = json::Value(json::ValueType::Object);
+            auto jv = env.rpc("json", "vault_info", to_string(jvParams));
+            checkError(
+                jv[jss::result],
+                "invalidParams",
+                RpcInvalidParams,
+                "Invalid field 'vault_id', not hex string.");
+        }
+
+        {
+            // An all-zero key is a well-formed request for a vault that cannot exist, not a
+            // malformed one. parseHex accepts both the padded form and the short "0".
+            testcase("RPC vault_info json all zero vault_id");
+            json::Value jvParams;
+            jvParams[jss::ledger_index] = jss::validated;
+            jvParams[jss::vault_id] = strHex(uint256(beast::kZero));
+            auto jv = env.rpc("json", "vault_info", to_string(jvParams));
             checkError(jv[jss::result], "entryNotFound", RpcEntryNotFound, "Entry not found.");
         }
 
         {
-            // An all-zero key is a well-formed request for a vault that cannot exist, not a
-            // malformed one.
-            testcase("RPC vault_info json all zero vault_id");
+            testcase("RPC vault_info json short zero vault_id");
             json::Value jvParams;
             jvParams[jss::ledger_index] = jss::validated;
-            jvParams[jss::vault_id] = strHex(uint256(beast::kZero));
+            jvParams[jss::vault_id] = "0";
             auto jv = env.rpc("json", "vault_info", to_string(jvParams));
             checkError(jv[jss::result], "entryNotFound", RpcEntryNotFound, "Entry not found.");
         }
@@ -5560,6 +5586,20 @@ class Vault_test : public beast::unit_test::Suite
                 "Invalid field 'owner', not AccountID.");
         }
 
+        {
+            testcase("RPC vault_info json array owner");
+            json::Value jvParams;
+            jvParams[jss::ledger_index] = jss::validated;
+            jvParams[jss::owner] = json::Value(json::ValueType::Array);
+            jvParams[jss::seq] = sequence;
+            auto jv = env.rpc("json", "vault_info", to_string(jvParams));
+            checkError(
+                jv[jss::result],
+                "actMalformed",
+                RpcActMalformed,
+                "Invalid field 'owner', not AccountID.");
+        }
+
         {
             testcase("RPC vault_info json invalid combination only owner");
             json::Value jvParams;
diff --git a/src/xrpld/rpc/handlers/VaultInfo.cpp b/src/xrpld/rpc/handlers/VaultInfo.cpp
index 5ed238e25b..0aa5334bd2 100644
--- a/src/xrpld/rpc/handlers/VaultInfo.cpp
+++ b/src/xrpld/rpc/handlers/VaultInfo.cpp
@@ -26,7 +26,9 @@ parseVault(json::Value const& params, json::Value& jvResult)
     uint256 uNodeIndex = beast::kZero;
     if (hasVaultId && !hasOwner && !hasSeq)
     {
-        if (!uNodeIndex.parseHex(params[jss::vault_id].asString()))
+        // asString() throws on an object or an array, so the type comes first.
+        auto const& vaultId = params[jss::vault_id];
+        if (!vaultId.isString() || !uNodeIndex.parseHex(vaultId.asString()))
         {
             rpc::injectError(
                 RpcInvalidParams, rpc::expectedFieldMessage(jss::vault_id, "hex string"), jvResult);
@@ -36,16 +38,19 @@ parseVault(json::Value const& params, json::Value& jvResult)
     }
     else if (!hasVaultId && hasOwner && hasSeq)
     {
-        auto const id = parseBase58<AccountID>(params[jss::owner].asString());
+        auto const& owner = params[jss::owner];
+        auto const id = owner.isString() ? parseBase58<AccountID>(owner.asString())
+                                         : std::optional<AccountID>{};
         if (!id)
         {
             rpc::injectError(
                 RpcActMalformed, rpc::expectedFieldMessage(jss::owner, "AccountID"), jvResult);
             return std::nullopt;
         }
-        if (!(params[jss::seq].isInt() || params[jss::seq].isUInt()) ||
-            params[jss::seq].asDouble() <= 0.0 ||
-            params[jss::seq].asDouble() > double(json::Value::kMaxUInt))
+
+        // Int and UInt are both 32 bits wide, so the type check is the only upper bound needed.
+        auto const& seqField = params[jss::seq];
+        if (!(seqField.isInt() || seqField.isUInt()) || seqField.asDouble() <= 0.0)
         {
             rpc::injectError(
                 RpcInvalidParams,
@@ -54,7 +59,7 @@ parseVault(json::Value const& params, json::Value& jvResult)
             return std::nullopt;
         }
 
-        auto const seq = SeqProxy::rawSequence(params[jss::seq].asUInt());
+        auto const seq = SeqProxy::rawSequence(seqField.asUInt());
         uNodeIndex = keylet::vault(*id, seq).key;
     }
     else