CVE-2026-26265
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedDiscourse 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceAn IDOR vulnerability in Discourse's DirectoryItemsController#index allows the user_field_ids parameter to bypass authorization checks, enabling anonymous users to retrieve private custom field values (phone numbers, addresses, etc.) for all users in the directory by simply specifying the field ID.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 2025.12.0>= 2026.1.0, < 2026.1.1= 2026.2.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check Discourse versionLocate the Discourse version file or check the admin dashboard for the installed version numberAffected if The version is less than 2025.12.0, OR between 2026.1.0 and 2026.1.1 exclusive, OR exactly 2026.2.0
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Verify user directory is enabledCheck the site setting enable_user_directory in Discourse admin panel or via APIAffected if The user directory setting is enabled (value is true) and the version is in the affected range above
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Identify private custom user fieldsReview custom user fields in admin panel under Users -> Custom Fields; check which fields have the public option disabled or are marked as privateAffected if There are custom user fields configured with private visibility and the version is affected
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Test anonymous directory accessSubmit a GET request to /directory.json with user_field_ids parameter specifying a private field ID while unauthenticatedAffected if The response returns private custom field data without authentication
You are affected if running an affected Discourse version AND the user directory is enabled AND private custom user fields exist that could be exposed via the user_field_ids parameter.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped2025.12.02026.1.1
Upgrade to Discourse versions 2025.12.2, 2026.1.1, or 2026.2.0 which implement filtering against UserField.public_fields; alternatively, disable the user directory via the enable_user_directory site setting or remove sensitive data from private user fields.
Discourse 2025.12.2, 2026.1.1, or 2026.2.0
- 1. Back up your Discourse instance database and files before performing any upgrade.
- 2. Upgrade Discourse to version 2025.12.2, 2026.1.1, or 2026.2.0 (choose the release branch matching your current installation).
- 3. After upgrade, verify the fix by testing the directory endpoint: attempt a request with a private user_field_id (e.g., GET /directory_items.json?period=all&user_field_ids=1) as a non-staff user and confirm the private field values are no longer exposed.
- 4. Review your user fields configuration to ensure sensitive fields are properly marked as non-public if they should remain private.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-26265 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-26265 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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- Version or environment caveats, and links to real fixes
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