Summary
Rocket.Chat's SAML integration in versions <8.5.0, <8.4.1, <8.3.3, <8.2.3, <8.1.4, <8.0.5, <7.13.7, and <7.10.11 does not verify the signature on inbound LogoutRequest messages. An unauthenticated remote attacker who knows a target user's SAML NameID - which major identity providers (Okta, Google Workspace, Microsoft Entra ID, JumpCloud) expose as the user's email address - can craft a valid-looking unsigned LogoutRequest and submit it to the SP logout endpoint. The server processes it as legitimate, immediately destroying the victim's session.
Because the attack requires no authentication and no interaction from the victim, it can be repeated in a loop against individual users or scripted across many accounts, effectively rendering the Rocket.Chat instance unusable for SAML-authenticated users.
julio-rocketchat Finder
Summary
Rocket.Chat's SAML integration in versions <8.5.0, <8.4.1, <8.3.3, <8.2.3, <8.1.4, <8.0.5, <7.13.7, and <7.10.11 does not verify the signature on inbound
LogoutRequestmessages. An unauthenticated remote attacker who knows a target user's SAML NameID - which major identity providers (Okta, Google Workspace, Microsoft Entra ID, JumpCloud) expose as the user's email address - can craft a valid-looking unsignedLogoutRequestand submit it to the SP logout endpoint. The server processes it as legitimate, immediately destroying the victim's session.Because the attack requires no authentication and no interaction from the victim, it can be repeated in a loop against individual users or scripted across many accounts, effectively rendering the Rocket.Chat instance unusable for SAML-authenticated users.