CVE-2025-49812

HIGH7.4

Apache HTTP Server: mod_ssl TLS upgrade attack

Published Jul 10, 2025

Modified 2 months ago

No fix available

Details

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.

References

WEBhttp://www.openwall.com/lists/oss-security/2025/07/09/3 WEBhttp://www.openwall.com/lists/oss-security/2025/07/10/2 WEBhttp://www.openwall.com/lists/oss-security/2025/07/10/9 ADVISORYhttps://httpd.apache.org/security/vulnerabilities_24.html WEBhttps://lists.debian.org/debian-lts-announce/2025/08/msg00009.html ADVISORYhttps://www.cve.org/CVERecord?id=CVE-2025-49812

CVSS Analysis

CVSS v3.1

7.4

Exploitability

Attack Vector

NetworkAV:N

Attack Complexity

HighAC:H

Privileges Required

NonePR:N

User Interaction

NoneUI:N

Scope

UnchangedS:U

Impact

Confidentiality

HighC:H

Integrity

HighI:H

Availability

NoneA:N

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

Weakness Type (CWE)

Authentication

CWE-287

Improper Authentication

Ecosystems

Timeline

PublishedJul 10, 2025

ModifiedNov 4, 2025