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

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.

Scores

EPSS (exploitation in 30 days)

0.44% · top 62% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: poc · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

• CWE-862: Missing Authorization (opens in a new tab)All about CWE-862 and its CVEs

Affected products

• kovidgoyal · calibre

  • affected < 9.12.0

References (3)

• https://github.com/kovidgoyal/calibre/security/advisories/GHSA-5x64-w63v-x2g6 (opens in a new tab)x_refsource_CONFIRMexploit
• https://github.com/kovidgoyal/calibre/commit/71295e8b62801e1ccecaa4fac47e6942f11cfe1e (opens in a new tab)x_refsource_MISC
• https://github.com/kovidgoyal/calibre/releases/tag/v9.12.0 (opens in a new tab)x_refsource_MISC

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-73249](https://trackcve.app/badge/CVE-2026-73249.svg)](https://trackcve.app/cve/CVE-2026-73249)

Record last updated 12 Aug 2026, 12:43 UTC.