CVE-2026-26265
Discourse has IDOR vulnerability in the directory items endpoint
Description
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, an IDOR vulnerability in the directory items endpoint allows any user, including anonymous users, to retrieve private user field values for all users in the directory. The `user_field_ids` parameter in `DirectoryItemsController#index` accepts arbitrary user field IDs without authorization checks, bypassing the visibility restrictions (`show_on_profile` / `show_on_user_card`) that are enforced elsewhere (e.g., `UserCardSerializer` via `Guardian#allowed_user_field_ids`). An attacker can request `GET /directory_items.json?period=all&user_field_ids=<id>` with any private field ID and receive that field's value for every user in the directory response. This enables bulk exfiltration of private user data such as phone numbers, addresses, or other sensitive custom fields that admins have explicitly configured as non-public. The issue is patched in versions 2025.12.2, 2026.1.1, and 2026.2.0 by filtering `user_field_ids` against `UserField.public_fields` for non-staff users before building the custom field map. As a workaround, site administrators can remove sensitive data from private user fields, or disable the user directory via the `enable_user_directory` site setting.
How to fix CVE-2026-26265
To remediate CVE-2026-26265, upgrade the affected package to a fixed version below.
- —upgrade to 2025.12.2 or later
Is CVE-2026-26265 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 2025.12.2, >= 2026.1.0, < 2026.1.1