fix: Endpoints /login and /verifyPassword disclose MFA secrets and protected fields when _User get is denied ([GHSA-75v4-m273-5j49](https://github.com/parse-community/parse-server/security/advisories/GHSA-75v4-m273-5j49)) (#10492)

spec/vulnerabilities.spec.js

@@ -6151,4 +6151,142 @@ describe('Vulnerabilities', () => {
       expect(req.info.clientSDK).toBeUndefined();
     });
   });
+
+  describe('(GHSA-75v4-m273-5j49) _User CLP refetch fallback leaks raw MFA secrets and protected fields', () => {
+    const headers = {
+      'X-Parse-Application-Id': 'test',
+      'X-Parse-REST-API-Key': 'rest',
+      'Content-Type': 'application/json',
+    };
+
+    const denyGetCLP = {
+      get: {},
+      find: {},
+      create: { '*': true },
+      update: { '*': true },
+      delete: {},
+    };
+
+    const updateUserCLP = classLevelPermissions =>
+      request({
+        method: 'PUT',
+        url: Parse.serverURL + '/schemas/_User',
+        headers: {
+          'X-Parse-Application-Id': 'test',
+          'X-Parse-Master-Key': 'test',
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify({ classLevelPermissions }),
+      });
+
+    async function setupMfaUser() {
+      const OTPAuth = require('otpauth');
+      const user = await Parse.User.signUp('victim', 'password');
+      const sessionToken = user.getSessionToken();
+      user.set('phone', '555-1234');
+      await user.save(null, { sessionToken });
+      const secret = new OTPAuth.Secret();
+      const totp = new OTPAuth.TOTP({ algorithm: 'SHA1', digits: 6, period: 30, secret });
+      await user.save(
+        { authData: { mfa: { secret: secret.base32, token: totp.generate() } } },
+        { sessionToken }
+      );
+      return { user, totp, secret };
+    }
+
+    beforeEach(async () => {
+      await reconfigureServer({
+        auth: {
+          mfa: { enabled: true, options: ['TOTP'], algorithm: 'SHA1', digits: 6, period: 30 },
+        },
+        protectedFields: { _User: { '*': ['phone'] } },
+        protectedFieldsOwnerExempt: false,
+      });
+    });
+
+    it('does not leak raw MFA secrets or protected fields from /verifyPassword when _User get CLP denies the re-fetch', async () => {
+      await setupMfaUser();
+      await updateUserCLP(denyGetCLP);
+
+      const response = await request({
+        method: 'POST',
+        url: Parse.serverURL + '/verifyPassword',
+        headers,
+        body: JSON.stringify({ username: 'victim', password: 'password' }),
+      });
+
+      expect(response.status).toBe(200);
+      expect(response.data.objectId).toBeDefined();
+      // Access control denied the re-fetch, so no stored fields may be disclosed
+      expect(response.data.authData).toBeUndefined();
+      expect(response.data.phone).toBeUndefined();
+    });
+
+    it('does not leak raw MFA secrets or protected fields from /login when _User get CLP denies the re-fetch', async () => {
+      const { totp } = await setupMfaUser();
+      await updateUserCLP(denyGetCLP);
+
+      const response = await request({
+        method: 'POST',
+        url: Parse.serverURL + '/login',
+        headers,
+        body: JSON.stringify({
+          username: 'victim',
+          password: 'password',
+          authData: { mfa: { token: totp.generate() } },
+        }),
+      });
+
+      expect(response.status).toBe(200);
+      // Login still succeeds and issues a session for the authenticated user
+      expect(response.data.objectId).toBeDefined();
+      expect(response.data.sessionToken).toBeDefined();
+      // But discloses no stored fields the caller may not read
+      expect(response.data.authData).toBeUndefined();
+      expect(response.data.phone).toBeUndefined();
+    });
+
+    it('sanitizes MFA secrets and protected fields on /verifyPassword when get CLP permits the re-fetch', async () => {
+      await setupMfaUser();
+
+      const response = await request({
+        method: 'POST',
+        url: Parse.serverURL + '/verifyPassword',
+        headers,
+        body: JSON.stringify({ username: 'victim', password: 'password' }),
+      });
+
+      expect(response.status).toBe(200);
+      expect(response.data.objectId).toBeDefined();
+      // afterFind replaces raw MFA material with a status flag
+      expect(response.data.authData.mfa.status).toBe('enabled');
+      expect(response.data.authData.mfa.secret).toBeUndefined();
+      expect(response.data.authData.mfa.recovery).toBeUndefined();
+      // protectedFieldsOwnerExempt:false strips protected fields even for the owner
+      expect(response.data.phone).toBeUndefined();
+    });
+
+    it('returns the full user to a master-key /verifyPassword even when get CLP is denied', async () => {
+      await setupMfaUser();
+      await updateUserCLP(denyGetCLP);
+
+      const response = await request({
+        method: 'POST',
+        url: Parse.serverURL + '/verifyPassword',
+        headers: {
+          'X-Parse-Application-Id': 'test',
+          'X-Parse-Master-Key': 'test',
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify({ username: 'victim', password: 'password' }),
+      });
+
+      expect(response.status).toBe(200);
+      expect(response.data.objectId).toBeDefined();
+      // Master bypasses CLP and protectedFields by design, so it still receives
+      // the full record (auth hierarchy preserved); the minimal denied-path
+      // response only applies to non-master callers.
+      expect(response.data.phone).toBe('555-1234');
+    });
+  });
 });

src/Routers/UsersRouter.js

@@ -370,10 +370,21 @@ export class UsersRouter extends ClassesRouter {
       );
       filteredUser = filteredUserResponse.results?.[0];
     } catch {
-      // re-fetch may fail for legacy users without ACL; fall through
+      // The re-fetch enforces `_User` `get` CLP and may be denied by access
+      // control (e.g. CLP `get: {}` or an ACL that excludes the caller).
+      // Handled below; never fall back to the raw row.
     }
     if (!filteredUser) {
-      filteredUser = user;
+      // Master/maintenance callers bypass CLP, protectedFields, and authData
+      // afterFind, so for them an empty re-fetch is a genuine not-found edge, not
+      // an access-control denial; they are entitled to the full row. For every
+      // other caller, an empty/denied re-fetch means access control withheld the
+      // record, so disclose only the identity — never the raw row, which would
+      // leak fields hidden by `protectedFields` and raw `authData` (e.g. MFA
+      // secrets and recovery codes) that the sanitizing re-fetch would remove.
+      // The session token is still attached below so login succeeds.
+      filteredUser =
+        req.auth.isMaster || req.auth.isMaintenance ? user : { objectId: user.objectId };
     }
     UsersRouter.removeHiddenProperties(filteredUser);
     filteredUser.sessionToken = user.sessionToken;
@@ -472,10 +483,20 @@ export class UsersRouter extends ClassesRouter {
           );
           filteredUser = filteredUserResponse.results?.[0];
         } catch {
-          // re-fetch may fail for legacy users without ACL; fall through
+          // The re-fetch enforces `_User` `get` CLP and may be denied by access
+          // control (e.g. CLP `get: {}` or an ACL that excludes the caller).
+          // Handled below; never fall back to the raw row.
         }
         if (!filteredUser) {
-          filteredUser = user;
+          // See handleLogIn: master/maintenance callers bypass CLP,
+          // protectedFields, and authData afterFind, so an empty re-fetch is a
+          // genuine not-found edge for them and they are entitled to the full
+          // row. For all other callers, an empty/denied re-fetch means access
+          // control withheld the record, so disclose only the identity rather
+          // than the raw row, which would leak protectedFields and raw authData
+          // (e.g. MFA secrets and recovery codes).
+          filteredUser =
+            req.auth.isMaster || req.auth.isMaintenance ? user : { objectId: user.objectId };
         }
         UsersRouter.removeHiddenProperties(filteredUser);
         return { response: filteredUser };