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.

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
bookwyrm-social bookwyrm unaffected
Version Status Constraints
0 affected ≤ 0.9.1

No data.

No data.

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Project Subscriptions

Vendors Products
Joinbookwyrm Subscribe
Bookwyrm Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/bookwyrm-social/bookwyrm cve-icon cve-icon
https://github.com/bookwyrm-social/bookwyrm/blob/v0.9.1/bookwyrm/views/interaction.py cve-icon cve-icon
https://github.com/geo-chen/oss/blob/main/bookwyrm.md#finding-2-authenticated-idor-in-favoriteunfavorite-allows-interaction-with-private-statuses cve-icon cve-icon
https://www.vulncheck.com/advisories/bookwyrm-through-0.9.1-missing-authorization-on-the-favorite-and-unfavorite-endpoints cve-icon cve-icon
History

Sat, 05 Sep 2026 10:15:00 +0000

Type Values Removed Values Added
Description 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.
Title BookWyrm through 0.9.1 Missing Authorization on the Favorite and Unfavorite Endpoints
First Time appeared Joinbookwyrm
Joinbookwyrm bookwyrm
Weaknesses CWE-639
CPEs cpe:2.3:a:joinbookwyrm:bookwyrm:*:*:*:*:*:*:*:*
Vendors & Products Joinbookwyrm
Joinbookwyrm bookwyrm
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-05T09:59:04.004Z

Reserved: 2026-09-05T01:59:19.567Z

Link: CVE-2026-86112

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-05T10:16:42.130

Modified: 2026-09-05T10:16:42.130

Link: CVE-2026-86112

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-05T11:30:05Z

Weaknesses