Raw vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-26065 is a critical-severity Path Traversal (CWE-22) vulnerability in Calibre-Ebook Calibre. Its CVSS base score is 9.3 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 42th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-26065 is a path traversal vulnerability (CWE-22) in the PDB readers of calibre, a cross-platform e-book manager used for viewing, converting, editing, and cataloging e-books. Versions 9.2.1 and below are affected, specifically both 132-byte and 202-byte header variants in the PDB readers. This flaw enables arbitrary file writes with arbitrary extensions and content to any location where the user has write permissions, with files written in binary ('wb') mode that silently overwrites existing files. Published on 2026-02-20, it carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
The vulnerability can be exploited by an attacker with low privileges (PR:L) over the network (AV:N) with low attack complexity and no user interaction beyond normal application use. Exploitation allows arbitrary file writes, enabling high confidentiality, integrity, and availability impacts, such as potential code execution by overwriting critical files like executables and denial of service through file corruption.
The issue has been addressed in calibre version 9.3.0. Security practitioners should recommend immediate upgrades to this version or later. Additional details are available in the GitHub security advisory at https://github.com/kovidgoyal/calibre/security/advisories/GHSA-vmfh-7mr7-pp2w and the fixing commit at https://github.com/kovidgoyal/calibre/commit/b6da1c3878c06eb1356cb0ec1106cb66e0e9bfb8.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-8341
Vulnerability Data
calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Versions 9.2.1 and below are vulnerable to Path Traversal through PDB readers (both 132-byte and 202-byte header variants) that allow arbitrary file writes with arbitrary extension and…
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arbitrary content anywhere the user has write permissions. Files are written in 'wb' mode, silently overwriting existing files. This can lead to potential code execution and Denial of Service through file corruption. This issue has been fixed in version 9.3.0.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.3.2
Mitigating Controls (NIST 800-53 r5) AI
Enforces the intended directory access authorizations that path traversal would otherwise bypass.
Input validation directly neutralizes special path elements before pathname construction occurs.
Least privilege reduces the impact of any unauthorized file access obtained via traversal.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.
PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches path traversal via static/dynamic analysis.
Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.
Application security requirements include rules for safe file handling and canonicalization.
Secure architecture principles require least-privilege file access and directory isolation.
Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.
Information access restriction limits which files an application may read or write.