CVE-2020-10719Network attack vector

Request smuggling via chunk-size integer overflow

Published May 26, 2020 · Updated Aug 4, 2024

HTTP request smuggling in Red Hat Undertow before 2.1.1.Final allows remote attackers to desynchronize HTTP message boundaries. ChunkReader shifts each hexadecimal chunk-size digit into a signed long without first checking for overflow, so an oversized value wraps before framing is enforced. No authentication or user interaction is required, and successful desynchronization can expose or alter requests processed on a shared connection.

CVSS severity6.5
Medium
EPSS probability1.00%
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 Red Hat Undertow before 2.1.1.Final allows remote attackers to desynchronize HTTP message boundaries. ChunkReader shifts each hexadecimal chunk-size digit into a signed long without first checking for overflow, so an oversized value wraps before framing is enforced. No authentication or user interaction is required, and successful desynchronization can expose or alter requests processed on a shared connection.

The record

CVE
CVE-2020-10719
Published
May 26, 2020
Updated
Aug 4, 2024
Vendor
Red Hat
Product
Undertow
Classifications
CWE-444, CAPEC-33, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 26, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=Versions before 2.1.1.Final

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · Undertowversion=Versions before 2.1.1.Final

Published CVSS scores

6.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
6.4NVDAV:N/AC:L/Au:N/C:P/I:P/A:N
6.5Red Hat, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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.

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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