CVE-2025-49812
HIGH7.4EPSS 0.45%Apache HTTP Server: mod_ssl TLS upgrade attack
Published: 7/10/2025Modified: 4/28/2026
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.
Affected packages (3)
- Alpine/apache2from 0, < 2.4.64-r0
- Bitnami/apachefrom 0, < 2.4.64
- Debian/apache2from 0, < 2.4.65-1~deb11u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
References (8)
- ADVISORYhttps://security.alpinelinux.org/vuln/CVE-2025-49812
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2025-49812
- WEBhttps://httpd.apache.org/security/vulnerabilities_24.html
- WEBhttps://lists.debian.org/debian-lts-announce/2025/08/msg00009.html
- WEBhttps://nvd.nist.gov/vuln/detail/CVE-2025-49812
- 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