CVE-2026-27810

calibre Vulnerable to HTTP Response Header Injection

State: Published
Severity: 6.4 Medium
Published: Feb 27, 2026
Updated: Mar 2, 2026
Reserved: Feb 24, 2026

Description

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 `content_disposition` 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.

Scores

CVSS	Score	Vector	Source
3.1	6.4 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N	GitHub_M

Weaknesses

CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')

Affected Products

Product	Versions
calibrekovidgoyal	< 9.4.0Affected

References

https://github.com/kovidgoyal/calibre/security/advisories/GHSA-5fpj-fxw7-8grw

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