How severe is CVE-2026-26064?

CVE-2026-26064 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-26064 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-26064?

CVE-2026-26064 affects Calibre-ebook Calibre. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-26064?

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-2026-26064 have an EU (EUVD) identifier?

Yes. CVE-2026-26064 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8035.

When was CVE-2026-26064 published?

CVE-2026-26064 was published on 2026-02-20 and last updated on 2026-06-17.

CVE-2026-26064

CVE-2026-26064 is a high-severity vulnerability in Calibre-ebook Calibre with a CVSS 3.x base score of 8.8. 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-22.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v4: 9.3
EPSS exploit prediction: 1% (56th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-8035
Weakness: CWE-22
Affected product: Calibre-ebook Calibre
Published: 2026-02-20
Last modified: 2026-06-17

Description

calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Versions 9.2.1 and below contain a Path Traversal vulnerability that allows arbitrary file writes anywhere the user has write permissions. On Windows, this leads to Remote Code Execution by writing a payload to the Startup folder, which executes on next login. Function extract_pictures only checks startswith('Pictures'), and does not sanitize '..' sequences. calibre's own ZipFile.extractall() in utils/zipfile.py does sanitize '..' via _get_targetpath(), but extract_pictures() bypasses this by using manual zf.read() + open(). This issue has been fixed in version 9.3.0.

Frequently asked questions

What is CVE-2026-26064?: calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Versions 9.2.1 and below contain a Path Traversal vulnerability that allows arbitrary file writes anywhere the user has write permissions. On Windows, this leads to Remote Code Execution by writing a payload to the Startup folder, which executes on next login. Function extract_pictures only checks startswith('Pictures'), and does not sanitize '..' sequences. calibre's own ZipFile.extractall() in utils/zipfile.py does sanitize '..' via _get_targetpath(), but extract_pictures() bypasses this by using manual zf.read() + open(). This issue has been fixed in version 9.3.0.
How severe is CVE-2026-26064?: CVE-2026-26064 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-26064 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-26064?: CVE-2026-26064 affects Calibre-ebook Calibre. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-26064?: 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-2026-26064 have an EU (EUVD) identifier?: Yes. CVE-2026-26064 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8035.
When was CVE-2026-26064 published?: CVE-2026-26064 was published on 2026-02-20 and last updated on 2026-06-17.

References

Affected products (1)

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

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