CVE-2026-63718Network attack vectorHinoki check available

HTTP response smuggling via forwarded Transfer-Encoding header

Published Oct 1, 2026 · Updated Oct 1, 2026

Response smuggling in Apache HTTP Server 2.4.30 through 2.4.68 allows attackers to inject extra HTTP responses via a crafted uWSGI backend reply. The mod_proxy_uwsgi response handler forwarded a backend Transfer-Encoding header instead of removing that hop-by-hop header, creating inconsistent response framing. Exploitation requires a configured uWSGI proxy route and control over a backend response; the documented consequence is response smuggling, not server code execution.

CVSS severityUnavailable
Unscored
EPSS probability0.50%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Response smuggling in Apache HTTP Server 2.4.30 through 2.4.68 allows attackers to inject extra HTTP responses via a crafted uWSGI backend reply. The mod_proxy_uwsgi response handler forwarded a backend Transfer-Encoding header instead of removing that hop-by-hop header, creating inconsistent response framing. Exploitation requires a configured uWSGI proxy route and control over a backend response; the documented consequence is response smuggling, not server code execution.

The record

CVE
CVE-2026-63718
Published
Oct 1, 2026
Updated
Oct 1, 2026
Vendor
The Apache Software Foundation
Product
Apache HTTP Server
Classifications
CWE-444
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 2026Record 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=2.4.30 <=2.4.68

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Apache Software Foundation · Apache HTTP Serverversion=2.4.30 <=2.4.68

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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