6.1
MediumCVSS 3.1 · from GitHub_M
CVE-2026-81509
nforwardauth: Unvalidated r parameter allows post-authentication open redirect
nforwardauth · Open redirect · CWE-601Affectednforwardauth
FixNo fix listed yet.
PublishedOct 26, 17:19 · GitHub_M
ScoredOct 26 · 6.1 · GitHub_M
Exploit code publicNone known · checked 22:18 UTC
ExploitedNone known · CISA KEV checked 22:30 UTC
What we know
No known exploitation. CISA KEV, checked 22:30 UTC.
No public exploit code known. Exploit-DB, Metasploit, Nuclei, checked 22:18 UTC.
An attacker only needs network access to the target. No login needed. CVSS: network, no privileges.
Someone has to open, click or run something first. CVSS: user interaction required.
Description
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.
From GitHub_M
Affected and fixed versions
ProductAffectedFixed innforwardauth< 1.5.1–
Exploit code
Exploit-DBnone knownMetasploitnone knownNucleinone known