---
id: CVE-2026-86112
title: >-
  BookWyrm through 0.9.1 fails to validate user visibility permissions in the
  Favorite and Unfavorite views, allowing authenticated attackers to favorite or
  unfavorite followers-only and direct statuses they cannot access
summary: >-
  BookWyrm through 0.9.1 fails to validate user visibility permissions in the
  Favorite and Unfavorite views, allowing authenticated attackers to favorite or
  unfavorite followers-only and direct statuses they cannot access. Attackers
  can PO…
severity: medium
cvss: 5.4
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N'
cwe:
  - CWE-639
vendor: bookwyrm-social
product: bookwyrm
affected:
  - bookwyrm <= 0.9.1
published: '2026-09-05'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T16:18:01.420'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86112'
references:
  - url: 'https://github.com/bookwyrm-social/bookwyrm'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/bookwyrm-social/bookwyrm/blob/v0.9.1/bookwyrm/views/interaction.py
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/geo-chen/oss/blob/main/bookwyrm.md#finding-2-authenticated-idor-in-favoriteunfavorite-allows-interaction-with-private-statuses
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/bookwyrm-through-0.9.1-missing-authorization-on-the-favorite-and-unfavorite-endpoints
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-10T14:19:13.810369Z'
epss: 0.00177
epssPercentile: 0.07525
ingestedAt: '2026-09-06T07:51:55.750Z'
---

## Overview

BookWyrm through 0.9.1 fails to validate user visibility permissions in the Favorite and Unfavorite views, allowing authenticated attackers to favorite or unfavorite followers-only and direct statuses they cannot access. Attackers can POST to the favorite endpoint with a status ID to create unauthorized interactions, trigger ActivityPub broadcasts, and enumerate private status IDs through response differentiation.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.