CVE-2026-81509
nforwardauth is a forward auth service that allows the use of a single authentication middleware for multiple sites.
Impact
nforwardauth is a forward auth service that allows the use of a single authentication middleware for multiple sites. Versions prior to 1.5.1 accept an unvalidated `r` query parameter on the `/login` endpoint and use them as the post-authentication redirect destination. An unauthenticated attacker can create a legitimate `nforwardauth` login URL that redirects a victim to an attacker-controlled website after the victim successfully authenticates. This issue may facilitate phishing and other social-engineering attacks by abusing the trust associated with the legitimate authentication domain. This vulnerability does not provide an unauthenticated ForwardAuth bypass. Version 1.5.1 contains a patch.
Affected products
| Product | Affected versions |
|---|---|
| Single Authentication Middleware For Multiple Sites. | before 1.5.1 |
Versions were read from the advisory text. No structured product data has been published for this record yet.