CVE-2025-49812Network attack vector

Session hijacking via TLS upgrade desynchronization

Published Jul 10, 2025 · Updated Nov 4, 2025

Improper authentication in Apache HTTP Server 2.4.63 and earlier allows man-in-the-middle attackers to hijack HTTP sessions. With mod_ssl configured as SSLEngine optional, HTTP message boundaries become desynchronized while a plaintext connection transitions to TLS. The attack requires a man-in-the-middle network position and the nondefault RFC 2817 upgrade path, permitting takeover of the victim's HTTP session without interrupting service.

CVSS severity7.4
High
EPSS probability0.56%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Apache HTTP Server 2.4.63 and earlier allows man-in-the-middle attackers to hijack HTTP sessions. With mod_ssl configured as SSLEngine optional, HTTP message boundaries become desynchronized while a plaintext connection transitions to TLS. The attack requires a man-in-the-middle network position and the nondefault RFC 2817 upgrade path, permitting takeover of the victim's HTTP session without interrupting service.

The record

CVE
CVE-2025-49812
Published
Jul 10, 2025
Updated
Nov 4, 2025
Vendor
The Apache Software Foundation
Product
Apache HTTP Server
Classifications
CWE-287, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 10, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.4.63

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache HTTP Serverversion=0 <=2.4.63

Published CVSS scores

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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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