VulnerabilityDeferred

CVE-2025-23167

A flaw in Node.js 20's HTTP parser allows improper termination of HTTP/1 headers using `\r\n\rX` instead of the required `\r\n\r\n`.

MEDIUM 6.5EPSS 0.51%

Does this matter?

Lower severity and a low EPSS score (0.51%). Track it; it rarely justifies an emergency change on its own.

Description

A flaw in Node.js 20's HTTP parser allows improper termination of HTTP/1 headers using `\r\n\rX` instead of the required `\r\n\r\n`. This inconsistency enables request smuggling, allowing attackers to bypass proxy-based access controls and submit unauthorized requests. The issue was resolved by upgrading `llhttp` to version 9, which enforces correct header termination. Impact: * This vulnerability affects only Node.js 20.x users prior to the `llhttp` v9 upgrade.

CVSS 3.0: 6.5 MEDIUMCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS: 0.51% probability · 42th percentile
CISA KEV: Not listed
Weakness: CWE-444
Source: support@hackerone.com

References

https://nodejs.org/en/blog/vulnerability/may-2025-security-releases

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.