# CVE-2026-73248 — kovidgoyal calibre

> As of 2026-08-12, CVE-2026-73248 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in kovidgoyal calibre, CVSS v4.0 8.5, EPSS 0.1% (4.5th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-73248 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-2026-73248?

calibre is an e-book manager. Prior to 9.12.0, calibre processes attacker-controlled composite_template metadata from a malicious EPUB, OPF, PDF, or similar file through program: and a nested template() call whose formatter does not inherit allow_python_templates=False, allowing a nested python: template to reach compile_python_template and execute arbitrary Python code when the file is opened or imported. This issue is fixed in version 9.12.0.

The record classifies CVE-2026-73248 under weakness classes [CWE-94](https://intel.threadlinqs.com/cwe/CWE-94), [CWE-95](https://intel.threadlinqs.com/cwe/CWE-95). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 55 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 8.5 — High (derived from score) (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **EPSS (FIRST):** 0.1% probability of exploitation in the next 30 days, higher than 4.5% 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-2026-73248 being exploited?

It currently carries a trending score of 31 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **kovidgoyal**: calibre

## How to fix CVE-2026-73248

No vendor patch reference has been recorded for CVE-2026-73248 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-2026-73248

No threat campaign in the Threadlinqs corpus currently references CVE-2026-73248, 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-4f7g-rjfp-hmvx)

**Other references**

- [github.com](https://github.com/kovidgoyal/calibre/commit/dac9990458374a81a5372a768bba6527d965aac8)
- [github.com (v9.12)](https://github.com/kovidgoyal/calibre/releases/tag/v9.12.0)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-73248
Full detection coverage and IOCs for threats exploiting CVE-2026-73248 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp