calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Prior to version 9.6.0, a path traversal vulnerability exists in Calibre' handling of images in Markdown and other similar text-based files allowing an attacker to include arbitrary files from the file system into the converted book. Additionally, missing authentication and server-side request forgery in the background-image endpoint in the ebook reader web view allow the files to be exfiltrated without additional interaction. Version 9.6.0 contains a fix.

calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Prior to version 9.6.0, a Server-Side Request Forgery vulnerability in the background-image endpoint of calibre e-book reader's web view allows an attacker to perform blind GET requests to arbitrary URLs and exfiltrate information out from the ebook sandbox. Version 9.6.0 patches the issue.

calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Prior to 9.5.0, a path traversal vulnerability in the RocketBook (.rb) input plugin (src/calibre/ebooks/rb/reader.py) allows an attacker to write arbitrary files to any path writable by the calibre process when a user opens or converts a crafted .rb file. This is the same bug class fixed in CVE-2026-26065 for the PDB readers, but the fix was never applied to the RB reader. This vulnerability is fixed in 9.5.0.

calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Prior to version 9.4.0, the calibre Content Server's brute-force protection mechanism uses a ban key derived from both remoteaddr and the X-Forwarded-For header. Since the X-Forwarded-For header is read directly from the HTTP request without any validation or trusted-proxy configuration, an attacker can bypass IP-based bans by simply changing or adding this header, rendering the brute-force protection completely ineffective. This is particularly dangerous for calibre servers exposed to the internet, where brute-force protection is the primary defense against credential stuffing and password guessing attacks. Version 9.4.0 contains a fix for the issue.

calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Prior to version 9.4.0, an HTTP Response Header Injection vulnerability in the calibre Content Server allows any authenticated user to inject arbitrary HTTP headers into server responses via an unsanitized contentdisposition query parameter in the /get/ and /data-files/get/ endpoints. All users running the calibre Content Server with authentication enabled are affected. The vulnerability is exploitable by any authenticated user and can also be triggered by tricking an authenticated victim into clicking a crafted link. Version 9.4.0 contains a fix for the issue.

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 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.

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 extractpictures only checks startswith('Pictures'), and does not sanitize '..' sequences. calibre's own ZipFile.extractall() in utils/zipfile.py does sanitize '..' via gettargetpath(), but extractpictures() bypasses this by using manual zf.read() + open(). This issue has been fixed in version 9.3.0.

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.

calibre is an e-book manager. Prior to 9.2.0, Calibre's CHM reader contains a path traversal vulnerability that allows arbitrary file writes anywhere the user has write permissions. On Windows (haven't tested on other OS's), this can lead to Remote Code Execution by writing a payload to the Startup folder, which executes on next login. This vulnerability is fixed in 9.2.0.

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.

Path traversal in Calibre <= 7.14.0 allow unauthenticated attackers to achieve arbitrary file read.

Unsanitized user-input in Calibre <= 7.15.0 allow users with permissions to perform full-text searches to achieve SQL injection on the SQLite database.

Unsanitized user-input in Calibre <= 7.15.0 allow attackers to perform reflected cross-site scripting.

linktolocalpath in ebooks/conversion/plugins/htmlinput.py in calibre before 6.19.0 can, by default, add resources outside of the document root.

calibre before 5.32.0 contains a regular expression that is vulnerable to ReDoS (Regular Expression Denial of Service) in htmlpreprocessrules in ebooks/conversion/preprocess.py.

Race condition issues were found in Calibre at devices/linuxmounthelper.c allowing unprivileged users the ability to mount any device to anywhere.

A untrusted search path issue was found in Calibre at devices/linuxmounthelper.c leading to the ability of unprivileged users to execute any program as root.

Input validation issues were found in Calibre at devices/linuxmounthelper.c which can lead to argument injection and elevation of privileges.

gui2/viewer/bookmarkmanager.py in Calibre 3.18 calls cPickle.load on imported bookmark data, which allows remote attackers to execute arbitrary code via a crafted .pickle file, as demonstrated by Python code that contains an os.system call.

The E-book viewer in calibre before 2.75 allows remote attackers to read arbitrary files via a crafted epub file with JavaScript.