Quick answers
- Is CVE-2026-86112 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-86112 being exploited in the wild.
- How severe is CVE-2026-86112?
- Medium severity, with a CVSS score of 5.4, published 5 September 2026.
- Which products and versions are affected?
- BookWyrm through 0.9.1.
- Is there a fix for CVE-2026-86112?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-86112 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-86112?
- Check whether you run BookWyrm at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
BookWyrm through version 0.9.1 fails to validate user visibility permissions in the Favorite and Unfavorite view handlers (bookwyrm/views/interaction.py). The vulnerability exists because the views retrieve a Status object by ID without checking whether the authenticated user has permission to view or interact with it. An authenticated attacker can POST directly to the favorite endpoint with any status ID, creating unauthorized favorites on private statuses, triggering ActivityPub broadcasts, and enumerating private status IDs through response differentiation (different HTTP responses for accessible vs. inaccessible statuses). The vulnerability requires authentication but allows cross-user interaction with restricted content.
Affected products
- BookWyrm BookWyrm through 0.9.1
Timeline
- 2026-09-05: disclosed