CVE-2026-27824 - CERT CVE
ID CVE-2026-27824
Sažetak calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Prior to version 9.4.0, the calibre Content Server's brute-force protection mechanism uses a ban key derived from both `remote_addr` and the `X-Forwarded-For` header. Since the `X-Forwarded-For` header is read directly from the HTTP request without any validation or trusted-proxy configuration, an attacker can bypass IP-based bans by simply changing or adding this header, rendering the brute-force protection completely ineffective. This is particularly dangerous for calibre servers exposed to the internet, where brute-force protection is the primary defense against credential stuffing and password guessing attacks. Version 9.4.0 contains a fix for the issue.
Reference
CVSS
Base: 5.3
Impact: 1.4
Exploitability:3.9
Pristup
VektorSloženostAutentikacija
NETWORK LOW NONE
Impact
PovjerljivostCjelovitostDostupnost
LOW NONE NONE
CVSS vektor CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Zadnje važnije ažuriranje 04-03-2026 - 16:39
Objavljeno 27-02-2026 - 20:21