CVE-2026-53511

calibre: Arbitrary Code Execution in Template Formatter via Book Metadata

HIGH
8.5
CVSS Score
Published: July 7, 2026 at 08:46 PM UTC
Updated: October 25, 2026 at 08:10 PM UTC
1 product affected across 1 vendorCalibre

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Severity
HIGH8.5
Exploit prediction
EPSS 0.2%
SSVC
PoC

Description

calibre is an e-book manager. Prior to 9.10.0, a malicious EPUB, OPF, or PDF file can execute arbitrary Python code when its metadata is read by calibre, including through Add books or Edit books, by embedding a custom column definition with a python: template in calibre:user_metadata that is passed unsanitized to exec() in the template formatter. This issue is fixed in version 9.10.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 9.10.0
Affected range stops below 9.10.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.5HIGHGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-94

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