Campaign Monitor security updates, in plain English

Campaign Monitor

719 sites report using it · on drupal.org · 1 security update explained here

This module connects a website to an email marketing service so visitors can join or leave mailing lists.

Below is every security update for Campaign Monitor 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.

Campaign Monitor

Moderately critical · 719 sites report using it · SA-CONTRIB-2026-326 · on drupal.org · Week of 11 November 2026

The module does not properly protect its administration pages from forged requests. Anyone without logging in could trick an administrator into clicking a malicious link. They could alter list settings but could not read any hidden information.

Who could do thisAnyone visiting the site. No login needed.
Does it apply to youA site is affected if an attacker embeds a link with the exact ID of a mailing list and tricks a user with the access right to administer the module into clicking it.
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 Campaign Monitor to 3.0.3.

For developers: what the fix changed

Added `_csrf_token: 'TRUE'` to the list enable, disable, and refresh routes in `campaignmonitor.routing.yml` and updated link generation in `CampaignMonitorListsController.php` to use routes so tokens are automatically appended.

Also in this release Updated the delete form description and redirect URL, and added a cache clear on list deletion.

3.0.2 to 3.0.3 4 commits, 3 files.

campaignmonitor.routing.yml +3 −0 fix
src/Controller/CampaignMonitorListsController.php +49 −68 fix
src/Form/CampaignMonitorListDeleteForm.php +5 −3

Full diff, 3.0.2 to 3.0.3

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

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.

For context: I work mainly with UK membership bodies, charities 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.

Campaign Monitor

Campaign Monitor

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