Internet2 Grouper before 5.6 allows authentication bypass when LDAP authentication is used in certain ways. This is related to internet2.middleware.grouper.ws.security.WsGrouperLdapAuthentication and the use of the UyY29r password for the M3vwHr account. This also affects Grouper for Web Services before 4.13.1.
The product uses an authentication mechanism to restrict access to specific users or identities, but the mechanism does not sufficiently prove that the claimed identity is correct.
Attackers may be able to bypass weak authentication faster and/or with less effort than expected.