CVE-2026-27810

calibre Vulnerable to HTTP Response Header Injection

MEDIUM
6.4
CVSS Score
Published: February 27, 2026 at 07:44 PM UTC
Updated: June 17, 2026 at 10:27 AM UTC
2 products affected across 2 vendorsCalibreCalibre

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Severity
MEDIUM6.4
Exploit prediction
EPSS 0.2%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 9.4.0
Affected range stops below 9.4.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

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

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.4MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-113

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