@workos/authkit-session has an Open Redirect via state-derived redirect target

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

4.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

EPSS

• CVE-2026-42565: 0.19% estimated exploitation activity in the next 30 days; percentile 9.13 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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 (e.g., https://evil.com/, //evil.com, or similar variants) may be returned to the application. If this value is used directly in a redirect (e.g., via an HTTP Location header, framework redirect helpers, or client-side navigation), it may cause the user to be redirected to an external, attacker-controlled site. Security Impact This issue may be used to facilitate phishing or user redirection attacks by leveraging the trust of the originating domain. For example, an attacker could craft a link that directs a user through a legitimate authentication flow and…

Published by the source

5 May 2026, 18:42 UTC

Last modified by the source

13 May 2026, 14:33 UTC

Source last checked

26 Oct 2026, 12:52 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-vvvv-983w-r7pv

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-vvvv-983w-r7pv

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# Patch Next advisory brief: CVE-2026-42565

Advisory: @workos/authkit-session has an Open Redirect via state-derived redirect target
IDs: CVE-2026-42565, GHSA-vvvv-983w-r7pv
Record: https://patchnext.com/advisories/cve-2026-42565 (revision 2, source checked 26 Oct 2026, 12:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @workos/authkit-session 0.5.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @workos/authkit-session: affected < 0.5.1; fixed in 0.5.1

## Suggested inspection (read-only)
- `npm ls @workos/authkit-session --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @workos/authkit-session.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-vvvv-983w-r7pv (OSV record GHSA-vvvv-983w-r7pv lists affected ranges: npm @workos/authkit-session >=0 <0.5.1 (fixed))
- Verified: https://github.com/advisories/GHSA-vvvv-983w-r7pv (GitHub-reviewed advisory GHSA-vvvv-983w-r7pv lists affected ranges: npm @workos/authkit-session >=0 <0.5.1)

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