CVE-2026-53511
Arbitrary Python execution via crafted e-book metadata in calibre
Is CVE-2026-53511 being exploited?
Not confirmed. CVE-2026-53511 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.15% probability of exploitation in the next 30 days.
How severe is CVE-2026-53511?
CVE-2026-53511 is rated High with a CVSS score of 8.5. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-53511?
Yes. A fix has been recorded for CVE-2026-53511. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-53511 affect?
CVE-2026-53511 affects calibre < 9.10.0 (desktop e-book manager). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-53511?
Update calibre to 9.10.0+ and avoid opening untrusted e-books.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Local arbitrary Python code execution when calibre reads crafted EPUB/OPF/PDF metadata; attacker can run code as the user, steal data, install malware.
Patch when possible
- affected< 9.10.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.