Vulnerability · Published Aug 11, 2026 · Assigned by GitHub_M
CVE-2026-73249calibre Content Server `/book-update-annotations` Missing Write Authorization Check Allows Unauthorized Annotation Modification
High 7.5
In plain English
A high-severity missing authorization in calibre from kovidgoyal. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
calibre is an e-book manager. Prior to 9.12.0, the calibre Content Server endpoint POST /book-update-annotations/{library_id}/{book_id}/{fmt} in src/calibre/srv/books.py omits needs_db_write=True, causing Router.dispatch() to skip ctx.check_for_write_access() before update_annotations() passes attacker-controlled JSON to db.merge_annotations_for_book(), which allows a readonly user or an anonymous user on an unauthenticated deployment to persist unauthorized book annotation changes. This issue is fixed in version 9.12.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | calibre | no fix listed | DEBIAN-CVE-2026-73249 |
| Debian:13 | calibre | no fix listed | DEBIAN-CVE-2026-73249 |
| Debian:14 | calibre | 9.12.0+ds+~0.10.6-1 | DEBIAN-CVE-2026-73249 |
| Ubuntu:22.04:LTS | calibre | no fix listed | UBUNTU-CVE-2026-73249 |
| Ubuntu:24.04:LTS | calibre | no fix listed | UBUNTU-CVE-2026-73249 |
| Ubuntu:26.04:LTS | calibre | no fix listed | UBUNTU-CVE-2026-73249 |
| Ubuntu:26.10 | calibre | no fix listed | UBUNTU-CVE-2026-73249 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| kovidgoyal | calibre | < 9.12.0 |
Weakness: CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N