Subscription flow broken after update to 5.117.0 due to malformed internal filter

Developer help Self-hosting
1

Hi everyone,

After updating Ghost to version 5.117.0, my subscription flow stopped working correctly. When a user subscribes, Ghost attempts to send the magic link, but returns a 400 error and fails silently. I discovered this is related to an invalid internal filter referencing a newsletter ID that was previously deleted (or at least, not visible in the admin panel anymore).
:magnifying_glass_tilted_left: What I found

The error appears consistently in the production.error.log as follows:

“message”: “Error parsing filter”,
“stack”: “QueryError: Query Error: unexpected character in filter at char 2\n(tags:+id:-67e539196fd4d6b\n------^\nExpecting ‘NOT’, ‘LBRACKET’, ‘NULL’, ‘TRUE’, ‘FALSE’, ‘NUMBER’, ‘NOW’, ‘LITERAL’, ‘STRING’, ‘CONTAINS’, ‘STARTSWITH’, ‘ENDSWITH’, ‘GT’, ‘LT’, ‘GTE’, ‘LTE’, got ‘AND’”,
“level”: “normal”,
“statusCode”: 400

The filter tags:+id:-67e539196fd4d6b is malformed and invalid in NQL.
:hammer_and_wrench: What I tried

Changing theme (to Casper and others)

Removing all content filters and routes

Disabling portal and newsletters from admin

Searching and deleting references in:

    custom_theme_settings

    settings

    routes.yaml

Exported the JSON and found the offending newsletter ID 67e539196fd4d6b149f85728 in the newsletters block

Tried deleting the newsletter from the DB, but got a foreign key constraint error

Had to manually delete related rows from:

    email_recipients

    email_batches

    emails

    Then the newsletters table

Even after that, Ghost kept throwing the error, possibly due to config cache or other leftover internal reference

:collision: Impact

The magic link for new subscribers fails

Ghost throws a 400 error with a broken filter

There's no clear way to clean this from the admin UI

This only started happening after upgrading to 5.117.0 — everything worked fine before

:folded_hands: Suggestion / Help request

There should be a more graceful way for Ghost to:

Ignore or skip malformed filters that no longer point to active objects

Cleanly delete newsletters (with cascading deletes for associated data)

Warn admins about internal config inconsistencies before or after upgrading

Any advice on how to fully clean this issue would be greatly appreciated — or if this should be escalated as a bug.

Thanks a lot!
—Edmundo