Cross-Site Request Forgery (CSRF) in @gitlawb/openclaude (CVE-2026-42073)
Summary
Vulnerability in @gitlawb/openclaude (CVE-2026-42073). Risk of unauthorized operations or information disclosure. Exploitable via error. Mitigation: upgrade to 0.5.1 or later.
Original description
The description as published by the source.
OAuth State Validation Bypass via error Parameter Causes Local Server DoS in MCP Auth Callback
Description
The OpenClaude MCP authentication flow starts a temporary local HTTP server to handle OAuth callbacks. To prevent CSRF attacks, the server validates a state parameter against an internally stored value. However, due to a logic flaw in the order of conditionals, an attacker can completely bypass this check and force the server to shut down — without knowing the state value at all.
The vulnerable code looks like this:
if (!error && state !== oauthState) {
rejectOnce(new Error('OAuth state mismatch - possible CSRF attack'))
return
}
if (error) {
cleanup()
rejectOnce(new Error(errorMessage))
return
}
When a request arrives with an error query parameter (e.g., ?error=anything), the first condition becomes false because !error evaluates to false. This means the CSRF check is never reached. Execution falls through to the second block, where cleanup() is called — shutting down the local server and terminating the user's active authentication session.
The attacker does not need to know the state value. Any request containing an error parameter is enough to trigger the shutdown.
Impact
- The user's OAuth flow is silently terminated mid-session
- The local callback server is shut down (Denial of Service)
- Can be triggered remotely via a malicious web page using a cross-origin request (CSRF)
-…
Source: GitHub Security Advisories (Global) 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-2026-42073 has been found in @gitlawb/openclaude.
Attackers can target a specific entry point like error over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: upgrade @gitlawb/openclaude to 0.5.1 or later.
If unsure, ask your IT team or search "@gitlawb/openclaude CVE-2026-42073" on the vendor's site.
CVE-2026-42073 (@gitlawb/openclaude) — CWE-352 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: error / state / false / poc.js
Patched: 0.5.1 — apply immediately
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.
CSRF (CWE-352) exists in @gitlawb/openclaude. Attackers reach the vulnerable code path via error without authentication.
Check the vendor advisory for the affected versions of @gitlawb/openclaude. Attack surface: error / state / false / poc.js.
Severity: Medium (CVSS 6.5/10). Risk of unauthorized operations or information disclosure.
Update to 0.5.1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r '@gitlawb/openclaude' . 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 '@gitlawb/openclaude' . | 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
@gitlawb/openclaudeを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade @gitlawb/openclaude to 0.5.1ステージング環境で 0.5.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
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。
Affected packages
References
- advisory nvd.nist.gov
- exploit github.com
- package github.com
- patch security-advisories@github.com
- web security-advisories@github.com
- web github.com