CVE-2025-49812

Updated on 10 Jul 2025

Severity

7.4 High severity

Details

CVSS score
7.4
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Overview

About vulnerability

In some mod_ssl configurations on Apache HTTP Server versions through to 2.4.63, an HTTP desynchronisation attack allows a man-in-the-middle attacker to hijack an HTTP session via a TLS upgrade.

Only configurations using “SSLEngine optional” to enable TLS upgrades are affected. Users are recommended to upgrade to version 2.4.64, which removes support for TLS upgrade.

Details

Affected packages:
apache2 @ 2.4.29 (+11 more)

In some mod_ssl configurations on Apache HTTP Server versions through to 2.4.63, an HTTP desynchronisation attack allows a man-in-the-middle attacker to hijack an HTTP session via a TLS upgrade.

Only configurations using “SSLEngine optional” to enable TLS upgrades are affected. Users are recommended to upgrade to version 2.4.64, which removes support for TLS upgrade.

Fixes