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 dispatch memo keyed on the request path alone

Published Sep 24, 2026
·
Updated

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 prepareaction 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.

Affected Software

1 affected component
cpan/Catalyst::Seal<0.03

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Catalyst::Seal to a version that resolves this vulnerability.

    Fixed in 0.03

Event History

Sep 24, 2026
CVE Published
via MITRE·09:54 PM
Data Sourced
via MITRE·09:54 PM
RemedyDescriptionWeakness
Data Sourced
via NVD·10:17 PM
DescriptionSeverityWeakness

Frequently Asked Questions

1

Which applications are most likely to be affected?

Applications using Catalyst::Seal before 0.03 are affected when routing for the same path can vary by request method, content type, scheme, or query. The authorization-bypass condition specifically requires a shallower action on the same path and a deeper, POST-only action protected by an auto() check.

2

What does an attacker need to do to trigger the issue?

An attacker can first send a request that causes a path to resolve differently, such as a GET to a POST-only path. A later request to that same path can then reuse the earlier dispatch result because the memo is keyed only by path.

3

Can this cause availability problems as well as authorization bypass?

Yes. A request that resolves to no action is memoised, so a GET to a POST-only path can cause later requests, including the valid POST, to fail without consulting dispatch types or setting an action.

4

How can administrators identify likely exploitation or impact?

Look for paths where requests with different methods, content types, schemes, or query values should select different actions. Test whether sending a mismatching request first, such as GET before a valid POST, causes subsequent requests to fail or reach a shallower route without the deeper controller's auto() authorization check.

5

What is the available remediation?

Upgrade Catalyst::Seal to version 0.03 or later. The affected versions are those before 0.03.

Contact

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