CVE-2026-84312

## Summary In the Casdoor SSO flow, the OAuth `state` parameter is hard-coded to `settings.CasdoorSettings.Application` — a value identical for every user and every login. The callback handler accepts whatever `state` the client sends without comparing it to anything stored in the user agent, enabling a login-CSRF: an attacker can force the victim's browser to authenticate as the *attacker*. ## Details `api/user/casdoor.go:92-117` (`GetCasdoorUri`): ```go func GetCasdoorUri(c *gin.Context) { clientId := settings.CasdoorSettings.ClientId redirectUri := settings.CasdoorSettings.RedirectUri state := settings.CasdoorSettings.Application // ← constant ... c.JSON(http.StatusOK, gin.H{ "uri": fmt.Sprintf( "%s/login/oauth/authorize?client_id=%s&response_type=code&redirect_uri=%s&state=%s&scope=read", endpoint, clientId, encodedRedirectUri, state), }) } ``` `api/user/casdoor.go:24-90` (`CasdoorCallback`): ```go type CasdoorLoginUser struct { Code string `json:"code" binding:"required,max=255"` State string `json:"state" binding:"required,max=255"` } func CasdoorCallback(c *gin.Context) { var loginUser CasdoorLoginUser if !cosy.BindAndValid(c, &loginUser) { return } ... // state is NEVER compared to a per-session value token, err := casdoorsdk.GetOAuthToken(loginUser.Code, loginUser.State) ... u, err := user.GetUser(claims.Name) // username from Casdoor's JWT ... userToken, err := user.GenerateJWT(u) // JWT minted for whatever user came back } ``` Compare with the OIDC implementation in `api/user/oidc.go:35-48`, which generates a random state, stores it in an `oidc_state` cookie, and validates it on the callback. Casdoor has no such check. ## Proof of Concept 1. Attacker initiates a Casdoor authorisation flow on their own browser, obtaining an authorisation `code` for *their* Casdoor account. 2. Attacker hosts a page that auto-submits the captured `