CVE-2019-17565Network attack vector

Request smuggling via chunked-body byte overconsumption

Published Mar 23, 2020 · Updated Aug 5, 2024

HTTP request smuggling in Apache Traffic Server allows remote attackers to inject requests through crafted chunked bodies. The HTTP tunnel miscalculates the final byte count for an initially buffered chunked body and lets a consumer read beyond that message boundary. An unauthenticated network client can desynchronize Traffic Server from an origin on a reused connection, causing appended bytes to be handled as a separate request.

CVSS severity9.8
Critical
EPSS probability3.17%
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 allows remote attackers to inject requests through crafted chunked bodies. The HTTP tunnel miscalculates the final byte count for an initially buffered chunked body and lets a consumer read beyond that message boundary. An unauthenticated network client can desynchronize Traffic Server from an origin on a reused connection, causing appended bytes to be handled as a separate request.

The record

CVE
CVE-2019-17565
Published
Mar 23, 2020
Updated
Aug 5, 2024
Vendor
The Apache Software Foundation
Product
Apache Traffic Server
Classifications
CWE-444, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2024Record 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=Apache Traffic Server 6.0.0 to 6.2.3, 7.0.0 to 7.1.8, and 8.0.0 to 8.0.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Traffic Serverversion=Apache Traffic Server 6.0.0 to 6.2.3, 7.0.0 to 7.1.8, and 8.0.0 to 8.0.5

Published CVSS scores

9.8UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
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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