CVE-2025-49812

High

Description

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.

SeverityHigh

CVSS7.4

Exploit probability—

Product

Apache Http Server

PublishedJul 10, 2025

First seenJul 10, 2025

Weakness typeCWE-287Improper authentication

How to fix

Update

apache http_server2.4.64 or later

Vendor advisories

httpd.apache.org/security/vulnerabilities_24.html

Affected products

Product	Affected versions	Fixed in
apache http_server	v < 2.4.64	2.4.64

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