CVE-2026-26265
Plain English Summary
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This vulnerability allows an attacker to access private user information, such as phone numbers and addresses, from all users in a Discourse forum, even if they are not logged in. It occurs because the system does not properly check permissions for certain user data fields, making it easy for anyone to exploit this flaw and collect sensitive information.
Technical 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.
CVSS Vector Analysis
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NExploit Resources
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Official References
Quick Information
Published
Feb 26, 2026
about 1 month ago
Last Modified
Mar 2, 2026
about 1 month ago
Vendor
discourse
Product
discourse
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