HTTP request smuggling via plus-prefixed Content-Length acceptance
Published Jul 7, 2021 · Updated Aug 3, 2024
HTTP request smuggling in Hyperium Hyper before 0.14.10 allows remote attackers to desynchronize HTTP/1 connections via malformed input. The HTTP/1 Content-Length parser passes header text to Rust's u64 FromStr implementation, which accepts a leading plus sign instead of rejecting non-digit input. Exploitation requires Hyper to run as an HTTP/1 server behind a proxy that forwards the malformed header after failing to parse it, allowing the endpoints to disagree about request-body boundaries and expose subsequent requests.
Summary
What happened
HTTP request smuggling in Hyperium Hyper before 0.14.10 allows remote attackers to desynchronize HTTP/1 connections via malformed input. The HTTP/1 Content-Length parser passes header text to Rust's u64 FromStr implementation, which accepts a leading plus sign instead of rejecting non-digit input. Exploitation requires Hyper to run as an HTTP/1 server behind a proxy that forwards the malformed header after failing to parse it, allowing the endpoints to disagree about request-body boundaries and expose subsequent requests.
The record
- CVE
- CVE-2021-32715
- Published
- Jul 7, 2021
- Updated
- Aug 3, 2024
- Vendor
- Hyperium
- Product
- Hyper
- Classifications
- CWE-444, CAPEC-33, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 7, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.14.10
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
- Hyper plus-prefixed Content-Length request exampleproof 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
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo