Peter Brady, Drupal developer and private AI consultant

Drupal security updates, in plain English · Module

Central Authentication System (CAS) Server

303 sites report using it · on drupal.org · 2 security updates explained here

This module turns the website into a central login hub that allows users to access other connected systems.

Below is every security update for Central Authentication System (CAS) Server that this site has covered, newest first. Each one says who could exploit it, whether it applies to your site, how urgent it is, and what to tell your developer. If your site uses this module and you are not sure which version, that is the first question to ask whoever looks after it.

Central Authentication System (CAS) Server

Moderately critical · 303 sites report using it · SA-CONTRIB-2026-135 · on drupal.org · Week of 9 September 2026

The module does not properly check the web address used to send users to a new page after they log out. Anyone visiting the site could trick a user into clicking a link that sends them to a malicious external website. They could not read any private information or change any data.

  • Who could do thisAnyone visiting the site. No login needed.
  • Does it apply to youA site is affected if an attacker can convince a user to click a specially crafted link.
  • Has it been used in attacksNo sign of it.
  • How urgentDrupal rates this moderately critical. Include it in your next routine update, within the month.

Tell your developerUpdate Central Authentication System (CAS) Server to 2.0.4 or 2.1.3, whichever branch you are on.

For developers: what the fix changed

The fix validates the service URL during logout in the UserActionController class by checking it against the configuration helper. If the service is invalid it returns an error message.

2.0.3 to 2.0.4 1 commit, 1 file.

  • src/Controller/UserActionController.php +6 −0 fix

Full diff, 2.0.3 to 2.0.4 · Full diff, 2.1.2 to 2.1.3

The comparison is against the release immediately before the fix. If your site is on an older release, more will have changed.

Central Authentication System (CAS) Server

Less critical · 303 sites report using it · SA-CONTRIB-2026-007 · on drupal.org · Week of 28 January 2026

The module does not properly clean up text provided by users before sending it to other systems. A person with an ordinary account could insert hidden code into their profile fields. They could not read or change any private data on the website.

  • Who could do thisOnly someone with a login on your site.
  • Does it apply to youA site is affected if a user can type code into a profile field and the site is set up to send that field to other systems.
  • Has it been used in attacksNo sign of it.
  • How urgentDrupal rates this less critical. Fix it with the next routine update.

Tell your developerUpdate Central Authentication System (CAS) Server to 2.0.3 or 2.1.2, whichever branch you are on.

For developers: what the fix changed

The fix replaces manual string concatenation with `DOMDocument` to build XML responses in `ProxyController` and `TicketValidationController`, ensuring that user-supplied attribute values are properly escaped and preventing XML element injection.

Also in this release The release also deprecates the use of the term 'whitelist' in favour of `loadServiceFromUri`, enforces coding standards with a new `phpcs.xml`, and updates tests accordingly.

2.0.2 to 2.0.3 7 commits, 9 files including 2 tests.

  • .cspell-project-words.txt +2 −0
  • phpcs.xml +12 −0
  • src/Configuration/ConfigHelper.php +9 −3
  • src/Controller/ProxyController.php +65 −26 fix
  • src/Controller/TicketValidationController.php +231 −121 fix
  • src/Controller/UserActionController.php +4 −4
  • src/Controller/XmlResponseBase.php +27 −0 fix

Full diff, 2.0.2 to 2.0.3 · Full diff, 2.1.1 to 2.1.2

The comparison is against the release immediately before the fix. If your site is on an older release, more will have changed.

Not sure what your site is running?

Send me your Drupal site's address.

I'll tell you what I can see from outside, what the Drupal 10 end of life on 9 December means for it, and what it would cost to have me keep it patched. There's no charge for that and no obligation. peter@peterbrady.co.uk

Get in touch

Tell me who you are, what your organisation does, and what you need. That might be a Drupal site that needs looking after, an upgrade to get done before December, or an agency that needs Drupal cover.

If I can help, I'll say so and suggest a call. If I can't, I'll tell you straight away rather than waste your time.

peter@peterbrady.co.uk

For context: I work mainly with UK charities, membership bodies and research organisations, and with the agencies that look after their websites. Not recruiters.

Or start smaller and connect with me on LinkedIn. That's where I post what I find digging around in charity and grants data, and where the free tools turn up first.

Peter Brady, Drupal developer and private AI consultant

PNB Technologies Limited
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Lancashire, L39 1NT, United Kingdom

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