CVE-2026-84312

Nginx UI: Casdoor SSO callback uses a constant state parameter (login CSRF)

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),
    })
}

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
}

Login CSRF, the victim is forced to authenticate as the attacker, leading to data exfiltration of anything the victim subsequently uploads or configures. Particularly dangerous when nginx-ui is used by an organisation where Casdoor maps internal identities, the attacker can attribute their changes to the victim.

The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.

CVE-2026-84312 has a CVSS score of 7.1 (High). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.9.10-0.20260703131214-23d1934099b0); upgrading removes the vulnerable code path.

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Mirror the OIDC implementation:

+ import (
+    "crypto/rand"
+    "crypto/subtle"
+    "encoding/hex"
+    ...
+ )

 func GetCasdoorUri(c *gin.Context) {
     ...
-    state := settings.CasdoorSettings.Application
+    b := make([]byte, 16)
+    if _, err := rand.Read(b); err != nil {
+        cosy.ErrHandler(c, err); return
+    }
+    state := hex.EncodeToString(b)
+    c.SetSameSite(http.SameSiteLaxMode)
+    c.SetCookie("casdoor_state", state, 600, "/", "",
+                cSettings.ServerSettings.EnableHTTPS, true)
     ...
 }

 func CasdoorCallback(c *gin.Context) {
+    expected, err := c.Cookie("casdoor_state")
+    if err != nil {
+        c.AbortWithStatusJSON(http.StatusBadRequest,
+            gin.H{"message":"missing state cookie"}); return
+    }
     var loginUser CasdoorLoginUser
     if !cosy.BindAndValid(c, &loginUser) { return }
+    if subtle.ConstantTimeCompare([]byte(expected), []byte(loginUser.State)) != 1 {
+        c.AbortWithStatusJSON(http.StatusBadRequest,
+            gin.H{"message":"invalid state"}); return
+    }
     ...
 }

1. What is CVE-2026-84312? CVE-2026-84312 is a high-severity improper authentication vulnerability in github.com/0xJacky/Nginx-UI (go), affecting versions < 1.9.10-0.20260703131214-23d1934099b0. It is fixed in 1.9.10-0.20260703131214-23d1934099b0. The application does not adequately verify the identity of a user, device, or process before granting access.
2. How severe is CVE-2026-84312? CVE-2026-84312 has a CVSS score of 7.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/0xJacky/Nginx-UI are affected by CVE-2026-84312? github.com/0xJacky/Nginx-UI (go) versions < 1.9.10-0.20260703131214-23d1934099b0 is affected.
4. Is there a fix for CVE-2026-84312? Yes. CVE-2026-84312 is fixed in 1.9.10-0.20260703131214-23d1934099b0. Upgrade to this version or later.
5. Is CVE-2026-84312 exploitable, and should I be worried? Whether CVE-2026-84312 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-84312 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-84312? Upgrade github.com/0xJacky/Nginx-UI to 1.9.10-0.20260703131214-23d1934099b0 or later.

Other vulnerabilities in github.com/0xJacky/Nginx-UI