What’s Vulnerable › Vulnerabilities

CVE-2026-73249: calibre Content Server `/book-update-annotations` Missing Write Authorization Check Allows Unauthorized Annotation Modification

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-11 · updated 2026-10-24
• Weakness: CWE-862

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 products

• kovidgoyal calibre: before 9.12.0

References

• https://github.com/kovidgoyal/calibre/commit/71295e8b62801e1ccecaa4fac47e6942f11cfe1e
• https://github.com/kovidgoyal/calibre/releases/tag/v9.12.0
• https://github.com/kovidgoyal/calibre/security/advisories/GHSA-5x64-w63v-x2g6
• https://github.com/kovidgoyal/calibre/security/advisories/GHSA-5x64-w63v-x2g6

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