CVE-2023-38522Network attack vector

Request smuggling via malformed field names

Published Jul 26, 2024 · Updated Nov 3, 2025

HTTP request smuggling in Apache Traffic Server 8.0.0 through 8.1.10 and 9.0.0 through 9.2.4 allows remote attackers to poison caches. The request-header parser accepts disallowed field-name characters instead of rejecting the request, then forwards the malformed field to an origin server. Exploitation requires an origin server that interprets the invalid field differently; the resulting desynchronization can route a hidden request or corrupt cached responses.

CVSS severity7.5
High
EPSS probability0.99%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTTP request smuggling in Apache Traffic Server 8.0.0 through 8.1.10 and 9.0.0 through 9.2.4 allows remote attackers to poison caches. The request-header parser accepts disallowed field-name characters instead of rejecting the request, then forwards the malformed field to an origin server. Exploitation requires an origin server that interprets the invalid field differently; the resulting desynchronization can route a hidden request or corrupt cached responses.

The record

CVE
CVE-2023-38522
Published
Jul 26, 2024
Updated
Nov 3, 2025
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 26, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 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=8.0.0 <=8.1.10
  2. Affected versionversion=9.0.0 <=9.2.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Traffic Serverversion=8.0.0 <=8.1.10; version=9.0.0 <=9.2.4

Published CVSS scores

7.5NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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.

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.

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Technologies

Your stack

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Your stack

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