CVE-2026-42565 is a medium-severity (CVSS 4.3) Open Redirect vulnerability in @workos/authkit-session. O3 Security confirms whether CVE-2026-42565 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
@workos/authkit-session: Open Redirect via state-derived redirect target
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
@workos/authkit-sessionnpmDescription
@workos/authkit-session is a toolkit for building WorkOS AuthKit framework integrations. Prior to 0.5.1, an open redirect vulnerability exists in AuthService.handleCallback due to insufficient validation of the returnPathname value derived from the OAuth state parameter. The state parameter is round-tripped through the identity provider (IdP) and can be influenced by an attacker. The handleCallback function decodes and returns returnPathname without enforcing restrictions on origin or scheme. As a result, attacker-controlled values may be returned to the application. If this value is used directly in a redirect, it may cause the user to be redirected to an external, attacker-controlled site. This vulnerability is fixed in 0.5.1.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @workos/authkit-session | all versions | 0.5.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @workos/authkit-session. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @workos/authkit-session to 0.5.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42565 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-42565 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-42565. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-42565 in your dependencies?
O3 detects CVE-2026-42565 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.