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.

The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4705 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4705-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                          Abhijith PA     July 29, 2026                                 https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : calibre     Version        : 5.12.0+dfsg-1+deb11u5     CVE ID         : CVE-2026-27810 CVE-2026-27824 CVE-2026-30853 CVE-2026-33205                      CVE-2026-33206

    Multiple vulnerabilities have been discovered in calibre, an e-book     manager.

    CVE-2026-27810

        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         `content_disposition` query parameter in the `/get/` and         `/data-files/get/` endpoints

    CVE-2026-27824

        The calibre Content Server's brute-force protection mechanism uses         a ban key derived from both `remote_addr` 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.

    CVE-2026-30853

        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.

    CVE-2026-33205

        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.

    CVE-2026-33206

        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.

    For Debian 11 bullseye, these problems have been fixed in version     5.12.0+dfsg-1+deb11u5.

    We recommend that you upgrade your calibre packages.

    For the detailed security status of calibre please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/calibre

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-7de23151cd advisory.

    Update to 9.6.0. Fixes rhbz#2452087

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-9cc418c23e advisory.

    Update to 9.6.0. Fixes rhbz#2452087

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2026-33206)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
330617	Debian dla-4705 : calibre - security update	Nessus	Debian Local Security Checks	Local	high
310685	Fedora 44 : calibre (2026-7de23151cd)	Nessus	Fedora Local Security Checks	Local	high
305101	Fedora 43 : calibre (2026-9cc418c23e)	Nessus	Fedora Local Security Checks	Local	high
304172	Linux Distros Unpatched Vulnerability : CVE-2026-33206	Nessus	Misc.	Local	high

Detections

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CVE-2026-33206

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Tenable Plugins

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