CVE-2026-27810
MEDIUMDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 11% of all known CVEs.
References
Related Vulnerabilities
Other CWE-113 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-37436 | Medium | 5.3 | 61% | - | Fix |
| CVE-2024-52875 | High | 8.8 | 30% | - | - |
| CVE-2016-5699 | Medium | 6.1 | 9.9% | - | Fix |
| CVE-2016-8024 | High | 8.1 | 8.7% | - | - |
| CVE-2017-17742 | Medium | 5.3 | 5.5% | - | Fix |
| CVE-2016-5325 | Medium | 6.1 | 4.1% | - | Fix |
Common questions
How do I fix CVE-2026-27810?
Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2026-27810 being actively exploited?
Not that we know of. CVE-2026-27810 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.21% is the estimated probability that it will be exploited in the next 30 days. That is higher than 11% of all scored CVEs.
How severe is CVE-2026-27810?
CVE-2026-27810 has a CVSS v3 base score of 6.4, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-27810 affect?
Published advisories record a fix for calibre (Debian), calibre (Windows application). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-17.