How severe is CVE-2026-25636?

CVE-2026-25636 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2026-25636 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-25636?

CVE-2026-25636 affects Calibre-ebook Calibre. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-25636?

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-2026-25636 have an EU (EUVD) identifier?

Yes. CVE-2026-25636 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5597.

When was CVE-2026-25636 published?

CVE-2026-25636 was published on 2026-02-06 and last updated on 2026-06-17.

CVE-2026-25636

CVE-2026-25636 is a high-severity vulnerability in Calibre-ebook Calibre with a CVSS 3.x base score of 8.2. 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-22.

Key facts

Severity: High (CVSS 3.x base score 8.2)
EPSS exploit prediction: 0% (11th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-5597
Weakness: CWE-22
Affected product: Calibre-ebook Calibre
Published: 2026-02-06
Last modified: 2026-06-17

Description

calibre is an e-book manager. In 9.1.0 and earlier, a path traversal vulnerability in Calibre's EPUB conversion allows a malicious EPUB file to corrupt arbitrary existing files writable by the Calibre process. During conversion, Calibre resolves CipherReference URI from META-INF/encryption.xml to an absolute filesystem path and opens it in read-write mode, even when it points outside the conversion extraction directory. This vulnerability is fixed in 9.2.0.

Frequently asked questions

What is CVE-2026-25636?: calibre is an e-book manager. In 9.1.0 and earlier, a path traversal vulnerability in Calibre's EPUB conversion allows a malicious EPUB file to corrupt arbitrary existing files writable by the Calibre process. During conversion, Calibre resolves CipherReference URI from META-INF/encryption.xml to an absolute filesystem path and opens it in read-write mode, even when it points outside the conversion extraction directory. This vulnerability is fixed in 9.2.0.
How severe is CVE-2026-25636?: CVE-2026-25636 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2026-25636 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-25636?: CVE-2026-25636 affects Calibre-ebook Calibre. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-25636?: 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-2026-25636 have an EU (EUVD) identifier?: Yes. CVE-2026-25636 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5597.
When was CVE-2026-25636 published?: CVE-2026-25636 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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