Open Redirect in clearance (CVE-2021-23435)
Summary
Vulnerability in clearance (CVE-2021-23435). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 2.5.0 or later.
Original description
The description as published by the source.
This affects the package clearance before 2.5.0. The vulnerability can be possible when users are able to set the value of session[:return_to]. If the value used for return_to contains multiple leading slashes (/////example.com) the user ends up being redirected to the external domain that comes after the slashes (http://example.com).
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
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-2021-23435 has been found in clearance.
Risk of unauthorized operations or information disclosure.
What to do: upgrade clearance to 2.5.0 or later.
If unsure, ask your IT team or search "clearance CVE-2021-23435" on the vendor's site.
CVE-2021-23435 (clearance) — CWE-601
Attack vector: remote (network-reachable) / unauthenticated
Patched: 2.5.0 — 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.
A vulnerability (CWE-601) exists in clearance.
Check the vendor advisory for the affected versions of clearance.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 2.5.0.
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 'clearance' . 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
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1Identify exposure identify
grep -r 'clearance' . | 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
clearance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 clearance to 2.5.0ステージング環境で 2.5.0 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。
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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
- advisory github.com
- package github.com
- web github.com
- web github.com
- web snyk.io