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, 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 . This product uses the NVD API but is not endorsed or certified by the NVD.