CVE-2023-38697
protocol-http1 HTTP Request/Response Smuggling vulnerability
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
protocol-http1 provides a low-level implementation of the HTTP/1 protocol. RFC 9112 Section 7.1 defined the format of chunk size, chunk data and chunk extension. The value of Content-Length header should be a string of 0-9 digits, the chunk size should be a string of hex digits and should split from chunk data using CRLF, and the chunk extension shouldn't contain any invisible character. However, Falcon has following behaviors while disobey the corresponding RFCs: accepting Content-Length header values that have `+` prefix, accepting Content-Length header values that written in hexadecimal with `0x` prefix, accepting `0x` and `+` prefixed chunk size, and accepting LF in chunk extension. This behavior can lead to desync when forwarding through multiple HTTP parsers, potentially results in HTTP request smuggling and firewall bypassing. This issue is fixed in `protocol-http1` v0.15.1. There are no known workarounds.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.75% · top 45% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.8.
Weakness
Affected products
- affected < 0.15.1
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- RubyGemsprotocol-http1GHSA-6jwc-qr2q-7xwj (opens in a new tab)
References (4)
- https://github.com/socketry/protocol-http1/security/advisories/GHSA-6jwc-qr2q-7xwj (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/socketry/protocol-http1/pull/20 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/socketry/protocol-http1/commit/e11fc164fd2b36f7b7e785e69fa8859eb06bcedd (opens in a new tab)x_refsource_MISCx_transferred
- https://www.rfc-editor.org/rfc/rfc9112#name-chunked-transfer-coding (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-6jwc-qr2q-7xwj (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2023-38697)Record last updated .