CVE-2026-27810

calibre Vulnerable to HTTP Response Header Injection

6.4 MediumFix available

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: Low
Availability: None

Exploit likelihood

0.24%Up 0.2 points since Feb 28, 2026

What each source reports

CVE List Score used 6.4

calibre Vulnerable to HTTP Response Header Injection

Record: CVE-2026-27810
CVSS 3.1: 6.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Weakness: CWE-113
Updated: 2026-11-02

EUVDEUVD-2026-9056 6.4

Record: EUVD-2026-9056
CVSS 3.1: 6.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Updated: 2026-11-02

NVD 6.4

Record: CVE-2026-27810
CVSS 3.1: 6.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Weakness: CWE-113
Updated: 2026-11-02

OSV 6.4

calibre Vulnerable to HTTP Response Header Injection

Record: CVE-2026-27810
CVSS 3.1: 6.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Weakness: CWE-113
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-27810 6.4

Record: DEBIAN-CVE-2026-27810
CVSS 3.1: 6.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-27810 6.4

Record: UBUNTU-CVE-2026-27810
CVSS 3.1: 6.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Updated: 2026-11-02

OSVopenSUSE-SU-2026:10587-1 No score

calibre-9.7.0-1.1 on GA media

These are all security issues fixed in the calibre-9.7.0-1.1 package on the GA media of openSUSE Tumbleweed.

Record: openSUSE-SU-2026:10587-1
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`calibre` Debian:12	before 6.13.0+repack-2+deb12u6, plus listed versions 6.13.0+repack-26.13.0+repack-2+deb12u16.13.0+repack-2+deb12u26.13.0+repack-2+deb12u36.13.0+repack-2+deb12u46.13.0+repack-2+deb12u5	6.13.0+repack-2+deb12u6
`calibre` Debian:13	before 8.5.0+ds-1+deb13u2, plus listed versions 8.5.0+ds-18.5.0+ds-1+deb13u1	8.5.0+ds-1+deb13u2
`calibre` Debian:14	before 9.4.0+ds+~0.10.5-1, plus listed versions 8.10.0+ds-18.10.0+ds-28.10.0+ds-38.11.0+ds+~0.10.5-18.11.1+ds+~0.10.5-1 Show 36 moreShow less 8.11.1+ds+~0.10.5-28.11.1+ds+~0.10.5-38.12.0+ds+~0.10.5-18.13.0+ds+~0.10.5-18.13.0+ds+~0.10.5-28.13.0+ds+~0.10.5-38.14.0+ds+~0.10.5-18.14.0+ds+~0.10.5-1~bpo13+18.15.0+ds+~0.10.5-18.15.0+ds+~0.10.5-1~bpo13+18.15.0+ds+~0.10.5-28.16.0+ds+~0.10.5-18.16.0+ds+~0.10.5-28.16.1+ds+~0.10.5-18.16.2+ds+~0.10.5-18.16.2+ds+~0.10.5-28.16.2+ds+~0.10.5-38.16.2+ds+~0.10.5-3~bpo13+18.5.0+ds-18.6.0+ds-18.7.0+ds-18.8.0+ds-18.8.0+ds-28.8.0+ds-2+gcc158.8.0+ds-38.9.0+ds-18.9.0+ds-28.9.0+ds-38.9.0+ds-49.0.0+ds+~0.10.5-19.1.0+ds+~0.10.5-19.2.0+ds+~0.10.5-19.2.1+ds+~0.10.5-19.2.1+ds+~0.10.5-29.3.0+ds+~0.10.5-19.3.1+ds+~0.10.5-1	9.4.0+ds+~0.10.5-1
`calibre` Ubuntu:16.04:LTS	All versions, plus listed versions 2.33.0+dfsg-1build12.38.0+dfsg-12.45.0+dfsg-12.45.0+dfsg-1build12.48.0+dfsg-1 Show 4 moreShow less 2.48.0+dfsg-1build12.54.0+dfsg-12.55.0+dfsg-12.55.0+dfsg-1ubuntu0.2	None known
`calibre` Ubuntu:18.04:LTS	All versions, plus listed versions 3.7.0+dfsg-23.7.0+dfsg-2build13.12.0+dfsg-13.13.0+dfsg-13.14.0+dfsg-1 Show 10 moreShow less 3.15.0.1+dfsg-13.16.0+dfsg-13.16.0+dfsg-1build13.17.0+dfsg-13.17.0+dfsg-23.18.0+dfsg-1build13.19.0+dfsg-13.20.0+dfsg-13.21.0+dfsg-13.21.0+dfsg-1build1	None known
`calibre` Ubuntu:20.04:LTS	All versions, plus listed versions 3.46.0+dfsg-14.2.0+dfsg-24.3.0+dfsg-14.3.0+dfsg-24.4.0+dfsg-1 Show 14 moreShow less 4.5.0+dfsg-14.5.0+dfsg-24.5.0+dfsg-34.6.0+dfsg-14.7.0+dfsg-14.99.3+dfsg-24.99.4+dfsg-14.99.4+dfsg-1build14.99.4+dfsg+really4.10.0+py3-24.99.4+dfsg+really4.11.2-14.99.4+dfsg+really4.11.2-1build14.99.4+dfsg+really4.12.0-14.99.4+dfsg+really4.12.0-1build14.99.4+dfsg+really4.12.0-1ubuntu1	None known
`calibre` Ubuntu:22.04:LTS	All versions, plus listed versions 5.25.0+dfsg-25.33.2+dfsg-15.34.0+dfsg-15.35.0+dfsg-1ubuntu25.37.0+dfsg-15.37.0+dfsg-1build1	None known
`calibre` Ubuntu:24.04:LTS	All versions, plus listed versions 6.24.0+ds-16.29.0+ds-17.0.0+ds-17.1.0+ds-17.1.0+ds-2 Show 9 moreShow less 7.2.0+ds-17.2.0+ds-1build17.3.0+ds-17.4.0+ds-17.5.1+ds-17.5.1+ds-27.5.1+ds-37.6.0+ds-17.6.0+ds-1build1	None known
`calibre` Ubuntu:25.10	All versions, plus listed versions 7.26.0+ds-4build18.3.0+ds-18.4.0+ds-18.5.0+ds-18.6.0+ds-1 Show 4 moreShow less 8.7.0+ds-18.8.0+ds-28.8.0+ds-38.8.0+ds-3build1	None known
`calibre` Ubuntu:26.10	All versions, plus listed versions 9.2.1+ds+~0.10.5-2build19.9.0+ds+~0.10.6-19.11.0+ds+~0.10.6-19.11.0+ds+~0.10.6-29.13.0+ds+~0.10.6-19.14.0+ds+~0.10.6-2build1	None known
`calibre` Ubuntu:26.04:LTS	All versions, plus listed versions 8.8.0+ds-3build18.13.0+ds+~0.10.5-38.14.0+ds+~0.10.5-18.15.0+ds+~0.10.5-18.16.0+ds+~0.10.5-2 Show 4 moreShow less 8.16.2+ds+~0.10.5-18.16.2+ds+~0.10.5-28.16.2+ds+~0.10.5-39.2.1+ds+~0.10.5-2build1	None known
`calibre` openSUSE:Tumbleweed From an advisory covering 10 CVEs	before 9.7.0-1.1	9.7.0-1.1

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 2, 2026	first indexed	CVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-27810 is a medium vulnerability (CVSS 6.4) in Calibre-ebook Calibre, published February 27, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.24%, the 15th percentile. Fixed in calibre 6.13.0+repack-2+deb12u6.

References

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