How severe is CVE-2026-25731?

CVE-2026-25731 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-25731 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-25731?

CVE-2026-25731 affects Calibre-ebook Calibre. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-25731?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-25731 have an EU (EUVD) identifier?

Yes. CVE-2026-25731 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5573.

When was CVE-2026-25731 published?

CVE-2026-25731 was published on 2026-02-06 and last updated on 2026-06-17.

CVE-2026-25731

CVE-2026-25731 is a high-severity vulnerability in Calibre-ebook Calibre with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1336.

Key facts

Severity: High (CVSS 3.x base score 7.8)
EPSS exploit prediction: 0% (15th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-5573
Weakness: CWE-1336
Affected product: Calibre-ebook Calibre
Published: 2026-02-06
Last modified: 2026-06-17

Description

calibre is an e-book manager. Prior to 9.2.0, a Server-Side Template Injection (SSTI) vulnerability in Calibre's Templite templating engine allows arbitrary code execution when a user converts an ebook using a malicious custom template file via the --template-html or --template-html-index command-line options. This vulnerability is fixed in 9.2.0.

Frequently asked questions

What is CVE-2026-25731?: calibre is an e-book manager. Prior to 9.2.0, a Server-Side Template Injection (SSTI) vulnerability in Calibre's Templite templating engine allows arbitrary code execution when a user converts an ebook using a malicious custom template file via the --template-html or --template-html-index command-line options. This vulnerability is fixed in 9.2.0.
How severe is CVE-2026-25731?: CVE-2026-25731 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-25731 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-25731?: CVE-2026-25731 affects Calibre-ebook Calibre. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-25731?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-25731 have an EU (EUVD) identifier?: Yes. CVE-2026-25731 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5573.
When was CVE-2026-25731 published?: CVE-2026-25731 was published on 2026-02-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:calibre-ebook:calibre:*:*:*:*:*:*:*:*

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