CVE-2026-58150Network attack vectorHinoki check available

Unauthenticated request smuggling via HTTP/2 downgrade

Published Jul 29, 2026 · Updated Jul 29, 2026

HTTP request smuggling in affected Apache Traffic Server releases allows remote attackers to desynchronize proxy and origin parsing. The HTTP/2 request path fails to reject the prohibited Transfer-Encoding header before downgrading the request for an HTTP/1 backend, causing the two hops to disagree about message boundaries. No authentication or user interaction is required, and a smuggled request can cross the proxy request boundary and affect downstream requests.

CVSS severity10.0
Critical
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

HTTP request smuggling in affected Apache Traffic Server releases allows remote attackers to desynchronize proxy and origin parsing. The HTTP/2 request path fails to reject the prohibited Transfer-Encoding header before downgrading the request for an HTTP/1 backend, causing the two hops to disagree about message boundaries. No authentication or user interaction is required, and a smuggled request can cross the proxy request boundary and affect downstream requests.

The record

CVE
CVE-2026-58150
Published
Jul 29, 2026
Updated
Jul 29, 2026
Vendor
The Apache Software Foundation
Product
Apache Traffic Server
Classifications
CWE-444, CAPEC-33, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 29, 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=10.0.0 <=10.1.3
  2. Affected versionversion=8.0.0 <=8.1.9
  3. Affected versionversion=9.0.0 <=9.2.14

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Traffic Serverversion=10.0.0 <=10.1.3; version=8.0.0 <=8.1.9; version=9.0.0 <=9.2.14

Published CVSS scores

10.0Apache Software FoundationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
7.8Apache Software FoundationCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:H/SA: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.

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

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-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CAPEC-33HTTP Request Smuggling
T1190Exploit Public-Facing Application

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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