CVE-2026-27810
HTTP Response Header Injection in calibre Content Server
Publication date: 2026-02-27
Last updated on: 2026-03-04
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| calibre-ebook | calibre | to 9.4.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-113 | The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is an HTTP Response Header Injection in the calibre Content Server prior to version 9.4.0. It allows any authenticated user to inject arbitrary HTTP headers into server responses by exploiting an unsanitized `content_disposition` query parameter in the `/get/` and `/data-files/get/` endpoints.
The vulnerability can also be triggered by tricking an authenticated user into clicking a specially crafted link, making it possible for attackers to manipulate server responses.
How can this vulnerability impact me? :
The vulnerability can impact you by allowing an authenticated user or an attacker who tricks an authenticated user to inject arbitrary HTTP headers into server responses. This can lead to security issues such as information disclosure or manipulation of how the server communicates with clients.
According to the CVSS score of 6.4, the impact includes low confidentiality and integrity impacts but no availability impact.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should upgrade the calibre Content Server to version 9.4.0 or later, as this version contains the fix for the HTTP Response Header Injection issue.
Additionally, consider restricting access to the Content Server and ensure that only trusted authenticated users can access it to reduce the risk of exploitation.