CVE-2026-85491 - CatalystSeal Vulnerability Details

CVE-2026-85491 - Catalyst::Seal Vulnerability Details

CVE-2026-85491 details a vulnerability in Catalyst::Seal versions before 0.03 for Perl. This flaw allows 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. 🚨

Key Issues:

• Catalyst::Seal replaces the dispatcher’s prepare_action with a version that memoizes how a path resolved: which dispatch type matched, at which level, and what was left over as arguments.
• The critical flaw is that the key is the request path and nothing else. This means 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.

Consequences:

• A path that resolves to no action is memoized as well, and replaying that entry returns without consulting any dispatch type, so no action is set and the request fails.
• For instance, a GET of a path whose action is declared POST-only therefore disables that path for every later request, including the correct POST.
• 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 memoizes 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.

Conclusion:

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.

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