Any Flarum user including unactivated can reply in public discussions whose first post was permanently deleted

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

3.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

EPSS

• CVE-2023-22489: 0.58% estimated exploitation activity in the next 30 days; percentile 47.76 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

If the first post of a discussion is permanently deleted but the discussion stays visible, any actor who can view the discussion is able to create a new reply via the REST API, no matter the reply permission or lock status. This includes users that don't have a validated email. Guests cannot successfully create a reply because the API will fail with a 500 error when the user ID 0 is inserted into the database. This should also be fixed to return the expected 401/403 status. This happens because when the first post of a discussion is permanently deleted, the firstpostid attribute of the discussion becomes null which causes access control to be skipped for all new replies. Flarum automatically makes discussions with zero comments invisible so an additional condition for this vulnerability is that the discussion must have at least one approved reply so that discussions.commentcount is still above zero after the post deletion. Impact This can open the discussion to uncontrolled spam or…

Published by the source

10 Jan 2023, 22:28 UTC

Last modified by the source

29 Jan 2023, 05:03 UTC

Source last checked

26 Oct 2026, 14:00 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-hph3-hv3c-7725

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# Patch Next advisory brief: CVE-2023-22489

Advisory: Any Flarum user including unactivated can reply in public discussions whose first post was permanently deleted
IDs: CVE-2023-22489, GHSA-hph3-hv3c-7725
Record: https://patchnext.com/advisories/cve-2023-22489 (revision 1, source checked 26 Oct 2026, 14:00 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: flarum/core 1.6.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist flarum/core: affected >= 1.3.0, < 1.6.3; fixed in 1.6.3

## Suggested inspection (read-only)
- Packagist flarum/core: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on flarum/core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-hph3-hv3c-7725 (GitHub-reviewed advisory GHSA-hph3-hv3c-7725 lists affected ranges: Packagist flarum/core >=1.3.0 <1.6.3)

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