CVE-2026-9733 Mojolicious::Plugin::Web::Auth::OAuth2 versions through 0.17 for Perl have an insecure default state parameter
An attacker can hijack user sessions via CSRF due to predictable OAuth2 state parameters generated from low-entropy sources.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-9733?
CVE-2026-9733 is a critical vulnerability in HAYAJO Mojolicious::Plugin::Web::Auth::OAuth2, published on 23 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Mojolicious::Plugin::Web::Auth::OAuth2 versions through 0.17 for Perl have an insecure default state parameter.
When no state generator is specified in the constructor, the module defaults to using a SHA-1 hash of predictable and low-entropy sources, including the epoch time (which is leaked via the HTTP Date header) and a call to Perl's built-in rand function.
A predictable state allows an attacker to hijack another user's session through cross site request forgery (CSRF).
Which versions are affected by CVE-2026-9733?
How do I fix CVE-2026-9733?
No fix has been published for CVE-2026-9733 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-9733 being exploited?
There is no known exploitation of CVE-2026-9733 in the wild and no public exploit code.
Sources
Also known as GHSA-rq65-66g5-5pg2.