# CVE-2026-73249 — kovidgoyal calibre

> As of 2026-08-12, CVE-2026-73249 is a HIGH-severity vulnerability in kovidgoyal calibre, CVSS v3.1 7.5, EPSS 0.2% (16.1th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-73249 as of 2026-08-12; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-12

## What is CVE-2026-73249?

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.

The record classifies CVE-2026-73249 under weakness class [CWE-862](https://intel.threadlinqs.com/cwe/CWE-862). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 55 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.5 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 16.1% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-11, last modified 2026-08-12

## Is CVE-2026-73249 being exploited?

It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **kovidgoyal**: calibre

## How to fix CVE-2026-73249

No vendor patch reference has been recorded for CVE-2026-73249 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-73249

No threat campaign in the Threadlinqs corpus currently references CVE-2026-73249, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on 2026-08-13. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com](https://github.com/kovidgoyal/calibre/security/advisories/GHSA-5x64-w63v-x2g6)

**Other references**

- [github.com](https://github.com/kovidgoyal/calibre/commit/71295e8b62801e1ccecaa4fac47e6942f11cfe1e)
- [github.com (v9.12)](https://github.com/kovidgoyal/calibre/releases/tag/v9.12.0)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-73249
Full detection coverage and IOCs for threats exploiting CVE-2026-73249 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp