CVE-2026-85491 Catalyst::Seal versions before 0.03 for Perl allow one request to disable a path or route a later one past an authorization check via a disp
Attackers can bypass authorization checks or disable routes by exploiting a flawed dispatch memoization cache in Catalyst::Seal.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-85491?
CVE-2026-85491 is a high-severity missing authorization vulnerability, published on 24 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Catalyst::Seal versions before 0.03 for Perl allow one request to disable a path or route a later one past an authorization check via a dispatch memo keyed on the request path alone.
Catalyst::Seal replaces the dispatcher's prepare_action with a version that memoises how a path resolved: which dispatch type matched, at which level, and what was left over as arguments. The key is the request path and nothing else. Action roles that match on the method, content type, scheme or query make that resolution depend on state the key does not carry, so the memo answers for a request it was not built from.
A path that resolves to no action is memoised as well, and replaying that entry returns without consulting any dispatch type, so no action is set and the request fails. A GET of a path whose action is declared POST-only therefore disables that path for every later request, the correct POST included. An entry that did resolve replays the level the earlier descent reached. Where a POST-only action sits below a shallower action on the same path, a GET memoises the shallow route, and a later POST is dispatched there with an auto() guarding the deeper controller never running.
The memo is cleared only when an action is registered, which happens at setup, so an entry lasts for the life of the process, and its cap of 2048 entries bounds how many paths one caller can disable. In the configuration measured, the misroute lands on the less privileged action, so it is an authorization check not running rather than a privilege gain.
Which versions are affected by CVE-2026-85491?
How do I fix CVE-2026-85491?
No fix has been published for CVE-2026-85491 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-85491 being exploited?
There is no known exploitation of CVE-2026-85491 in the wild and no public exploit code.
Sources
Also known as GHSA-5qhg-xgvp-wq2g.