| Title | Gitlawb openclaude 0.27.0 Denial of Service |
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| Description | The xAI OAuth loopback callback server (src/services/api/xaiOAuthCallback.ts) evaluates the error query parameter before performing CSRF state parameter validation.
This vulnerability is an unpatched sibling variant of disclosed advisory GHSA-c73c-x77g-854r ("MCP OAuth Callback: State Check Bypass via error Param Leads to DoS"). While the fix for GHSA-c73c-x77g-854r reordered checks in src/services/mcp/auth.ts and src/services/mcp/xaaIdpCallback.ts to validate state before processing errors, the xAI OAuth loopback callback handler was omitted during remediation.
When an unauthenticated request containing ?error=... is received on http://127.0.0.1:56121/callback, xaiOAuthCallback.ts marks the flow as settled and rejects waitForCallback() without verifying whether a valid state parameter was supplied.
Because the callback server runs on a fixed port (56121), any malicious website visited by the user while an xAI OAuth login is in progress can issue a cross-origin GET request (e.g., via <img src="..."> or fetch(..., {mode: 'no-cors'})) to immediately abort the victim's authentication attempt. |
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| Source | ⚠️ https://github.com/Gitlawb/openclaude/issues/2101 |
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| User | nedlir (UID 95981) |
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| Submission | 08/07/2026 16:17 (1 month ago) |
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| Moderation | 09/13/2026 11:37 (1 month later) |
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| Status | Accepted |
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| VulDB entry | 403266 [Gitlawb openclaude up to 0.30.0 xAI OAuth Callback xaiOAuthCallback.ts waitForCallback Error denial of service] |
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| Points | 20 |
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