Authentication Bypass in Nginx-UI (CVE-2026-84312)
Summary
Authentication bypass in Nginx-UI (CVE-2026-84312). Confidential information can be exposed externally. Exploitable via state.
Original description
The description as published by the source.
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):
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):
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
...
user…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-84312 has been found in Nginx-UI.
Attackers can target a specific entry point like state over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Nginx-UI CVE-2026-84312" on the vendor's site.
CVE-2026-84312 (Nginx-UI) — CWE-287 / CVSS v3 7.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: state / settings.CasdoorSettings.Application / GetCasdoorUri / CasdoorCallback
Workaround: Disable Casdoor SSO until patched.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Authentication bypass (CWE-287) exists in Nginx-UI. Attackers reach the vulnerable code path via state without authentication.
Check the vendor advisory for the affected versions of Nginx-UI. Attack surface: state / settings.CasdoorSettings.Application / GetCasdoorUri / CasdoorCallback.
Severity: High (CVSS 7.1/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Workaround: Disable Casdoor SSO until patched.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Nginx-UI' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Nginx-UI' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Nginx-UIを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
Disable Casdoor SSO until patched.パッチが適用されるまでの応急処置として、Disable Casdoor SSO until patched. を実施。回避策の副作用 (機能低下) を確認した上で。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。