kovidgoyal calibre up to 9.11.x Content Server src/calibre/srv/books.py Router.dispatch improper authorization

Summaryinfo

A vulnerability was found in kovidgoyal calibre up to 9.11.x. It has been rated as problematic. This vulnerability affects the function Router.dispatch of the file src/calibre/srv/books.py of the component Content Server. The manipulation leads to improper authorization. This vulnerability is uniquely identified as CVE-2026-73249. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in kovidgoyal calibre up to 9.11.x and classified as problematic. This issue affects the function Router.dispatch of the file src/calibre/srv/books.py of the component Content Server. The manipulation with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is integrity. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-73249 since 08/11/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1548.002 according to MITRE ATT&CK.

Upgrading to version 9.12.0 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• kovidgoyal

Name

• calibre

Version

• 9.0
• 9.1
• 9.2
• 9.3
• 9.4
• 9.5
• 9.6
• 9.7
• 9.8
• 9.9
• 9.10
• 9.11

Website

• Product: https://github.com/kovidgoyal/calibre/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion