What’s Vulnerable › Vulnerabilities
CVE-2026-26265: Discourse has IDOR vulnerability in the directory items endpoint
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.3% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2026-02-26 · updated 2026-06-17
- Weakness: CWE-863
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.
Affected products
- discourse: before 2025.12.0; from 2026.1.0 before 2026.1.1; 2026.2.0 — fixed in 2025.12.0, 2026.1.1
How to fix
Upgrade to a fixed version: discourse 2025.12.0, 2026.1.1. Check the vendor advisory for mitigations.
References
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