Improper Neutralization of Special Elements Used in a Template Engine in Calibre - CVE-2026-25731
Published: June 29, 2026
Vulnerability identifier: #VU135808
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2026-25731
CWE-ID: CWE-1336
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Calibre
Affected software:
Calibre
Calibre
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to server-side template injection in the HTML export feature when processing crafted template content during conversion. A remote attacker can embed template expressions in a crafted input to execute arbitrary code.
User interaction is required to open or convert crafted content.
How to mitigate CVE-2026-25731
Install security update from vendor's website.