CVE-2025-49812 | Apache HTTP Server: mod_ssl TLS upgrade attack

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.

Published: 2025-07-10 Last update: 2025-11-04 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-49812 is rated Moderate Risk (52.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.46%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-49812

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-03 0.45% 0.46% +0.01%
2 2026-05-06 0.08% 0.45% +0.37%
3 2025-12-05 — 0.08% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-49812

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.4 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 5.2 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2025-49812

OS Trackers for CVE-2025-49812

vendor priority summary link
alpine — CVE-2025-49812: 1 source package rows (apache2); 5 state rows across 5 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 5, open 0. https://security.alpinelinux.org/vuln/CVE-2025-49812
debian not yet assigned CVE-2025-49812 not yet assigned priority: Debian including 1 source packages (apache2), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2025-49812
redhat medium — https://access.redhat.com/security/cve/CVE-2025-49812
suse high — https://www.suse.com/security/cve/CVE-2025-49812/
ubuntu medium CVE-2025-49812 medium priority: Ubuntu including 1 source packages (apache2), 9 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): released 8, needs-triage 1. https://ubuntu.com/security/CVE-2025-49812

Affected software / configurations for CVE-2025-49812

Vendor Product Version Raw CPE
apache http_server < 2.4.64 cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*

References for CVE-2025-49812

cvelogic Threat Intelligence