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Vulnerabilities

Vulnerability · CVE-2026-27810

calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books.

Published Feb 27, 2026 · catalog updated Jun 17, 2026 · calibre is a cross-platform

Check if you run it

No confirmed exploitation is on record for CVE-2026-27810. EPSS is 0.33%. Act only if a listed version of calibre is a cross-platform is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (calibre is a cross-platform).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.4
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.33%
Remediation
Advisory link
Affected products
cpe calibre-ebook/calibre

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 query parameter in the and 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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe calibre-ebook/calibreversion unspecified

How to fix CVE-2026-27810

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-27810. EPSS is 0.33%. Act only if a listed version of calibre is a cross-platform is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-113. EPSS 0.33%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 27, 2026 · NIST NVD

    Detected

    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 query parameter in the and endpoints. All users running the calibre Content Server with authe

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 query parameter in the and endpoints. All users running the calibre Content Server with authe

Sources

  • CVE.orgVulnerability recordCVE-2026-27810

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-27810

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-27810

    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 re

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.