Calibre
CVE-2026-26064
HIGH
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessUpload malicious ZIP with traversal paths
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Exploitextract_pictures() bypasses sanitization
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ExecutionWrite payload to Windows Startup folder
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ImpactPayload executes on next user login
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V5 - File Handling Path canonicalization, traversal prevention
MITRE ATT&CK
2 techniques across 2 tactics: Discovery, Collection The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Authenticated user account required (PR:L). Victim must have write permissions to Windows Startup folder. Requires calibre versions 9.2.1 and below processing a specially crafted ZIP file containing '../' sequences in picture paths. |
| Impact | CVSS 8.8 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: Low. User interaction: None. Exploitable via remote/network. Public exploit/POC available. |
| Exploit ScenarioDerived | A remote attacker could exploit this flaw, Remote Code Execution by writing a payload to the Startup fo. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Remote code execution in Calibre 9.2.1 and earlier allows authenticated users to write arbitrary files via a path traversal flaw in the extract_pictures() function that fails to properly sanitize directory traversal sequences. On Windows systems, attackers can exploit this to write malicious payloads to the Startup folder, achieving code execution upon the next user login. Public exploit code exists for this vulnerability, and a patch is available in version 9.3.0.
Earlier versions of this analysis (1)
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. [CVSS 8.8 HIGH]
RemediationAI
A vendor patch is available — apply it immediately. Fixed in version 9.3.0.. Validate and sanitize file path inputs. Use allowlists. Restrict network access to the affected service where possible.
Affects your stack
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Technical ContextAI · show details
Classified as CWE-22 (Path Traversal). Affects Calibre. 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
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
Lifecycle Timeline
3DescriptionGitHub Advisory
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.
Executive ViewAI
Calibre versions 9.2.1 and below contain a critical path traversal vulnerability (CVE-2026-26064) that enables attackers to write arbitrary files to any location where the application has write permissions, potentially compromising system integrity and data security. Organizations using affected versions face immediate risk of unauthorized file creation, malware injection, and system compromise, requiring urgent patching to mitigate exposure.
Apply vendor patch.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Path traversal exploits occur when applications use user-controlled input to construct file system paths without proper validation.
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
Affected Products (CPE)GitHub Advisory
Calibre versions 9.2.1 and below allow authenticated users to write arbitrary files with any extension to any writable l
Remote code execution in Calibre prior to version 9.2.0 through a path traversal flaw in the CHM reader allows local att
Calibre 9.1.0 and earlier contains a path traversal vulnerability in EPUB conversion that allows malicious EPUB files to
calibre is an e-book manager. [CVSS 7.8 HIGH]
gui2/viewer/bookmarkmanager.py in Calibre 3.18 calls cPickle.load on imported bookmark data, which allows remote attacke
Path traversal in Calibre <= 7.14.0 allow unauthenticated attackers to achieve arbitrary file read. Rated high severity
link_to_local_path in ebooks/conversion/plugins/html_input.py in calibre before 6.19.0 can, by default, add resources ou
calibre before 5.32.0 contains a regular expression that is vulnerable to ReDoS (Regular Expression Denial of Service) i
Unsanitized user-input in Calibre <= 7.15.0 allow users with permissions to perform full-text searches to achieve SQL in
HTTP response header injection in Calibre Content Server prior to version 9.4.0 permits authenticated users to inject ar
Unsanitized user-input in Calibre <= 7.15.0 allow attackers to perform reflected cross-site scripting. Rated medium seve
The E-book viewer in calibre before 2.75 allows remote attackers to read arbitrary files via a crafted epub file with Ja
Exploit-DB