HTTP request smuggling via stale chunked-header state
Published Jan 6, 2021 · Updated Apr 30, 2025
HTTP request smuggling in Node.js before 10.23.1, 12.20.1, 14.15.4, and 15.5.1 allows remote attackers to bypass HTTP intermediaries. The HTTP parser retains F_CHUNKED from the first Transfer-Encoding header and fails to reevaluate it when a duplicate header changes the final coding token. Exploitation requires an HTTP/1.1 intermediary and back end to parse duplicate Transfer-Encoding headers differently, enabling authorization bypass or request misrouting.
Summary
What happened
HTTP request smuggling in Node.js before 10.23.1, 12.20.1, 14.15.4, and 15.5.1 allows remote attackers to bypass HTTP intermediaries. The HTTP parser retains F_CHUNKED from the first Transfer-Encoding header and fails to reevaluate it when a duplicate header changes the final coding token. Exploitation requires an HTTP/1.1 intermediary and back end to parse duplicate Transfer-Encoding headers differently, enabling authorization bypass or request misrouting.
The record
- CVE
- CVE-2020-8287
- Published
- Jan 6, 2021
- Updated
- Apr 30, 2025
- Vendor
- Node.js
- Product
- Node.js
- Classifications
- CWE-444, CAPEC-33, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 6, 2021CVE publishedPublication date reported by the CVE source.
- Apr 30, 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.
- Affected versionversion=10.0 <10.23.1
- Affected versionversion=11.0 <11.*
- Affected versionversion=12.0 <12.20.1
- Affected versionversion=13.0 <13.*
- Affected versionversion=14.0 <14.15.4
- Affected versionversion=15.0 <15.5.1
- Affected versionversion=4.0 <4.*
- Affected versionversion=5.0 <5.*
- Affected versionversion=6.0 <6.*
- Affected versionversion=7.0 <7.*
- Affected versionversion=8.0 <8.*
- Affected versionversion=9.0 <9.*
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
- HackerOne report 1002188proof of concept · unverified
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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