Request smuggling via non-CRLF header delimiters
Published Dec 5, 2022 · Updated Apr 30, 2025
HTTP request smuggling in Node.js 14.x, 16.x, and 18.x allows remote attackers to inject requests via malformed header delimiters. The http module's llhttp parser accepts header fields not terminated by the required CRLF sequence, causing intermediaries and Node.js to disagree on request boundaries. Exploitation requires a network-facing Node.js HTTP server behind an intermediary that parses the crafted stream differently, enabling cache poisoning or security-control bypass.
Summary
What happened
HTTP request smuggling in Node.js 14.x, 16.x, and 18.x allows remote attackers to inject requests via malformed header delimiters. The http module's llhttp parser accepts header fields not terminated by the required CRLF sequence, causing intermediaries and Node.js to disagree on request boundaries. Exploitation requires a network-facing Node.js HTTP server behind an intermediary that parses the crafted stream differently, enabling cache poisoning or security-control bypass.
The record
- CVE
- CVE-2022-35256
- Published
- Dec 5, 2022
- Updated
- Apr 30, 2025
- Vendor
- Node.js
- Product
- Node.js
- Classifications
- CWE-444, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 5, 2022CVE 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.*
- Affected versionversion=11.0 <11.*
- Affected versionversion=12.0 <12.*
- Affected versionversion=13.0 <13.*
- Affected versionversion=14.0 <14.20.1
- Affected versionversion=15.0 <15.*
- Affected versionversion=16.0 <16.17.1
- Affected versionversion=17.0 <17.*
- Affected versionversion=18.0 <18.9.1
- 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 1675191proof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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