CVE-2026-66357
Description
A flaw was found in the inets component of Erlang/OTP, specifically within its httpd server. This vulnerability arises from the httpd server's failure to correctly implement obs-fold (obsolete line folding) for HTTP header continuation lines, as defined in RFC 2616 and RFC 7230. This oversight allows a remote attacker to perform HTTP Request Smuggling attacks by crafting malicious HTTP requests. Such attacks can lead to bypassing security mechanisms, poisoning web caches, or gaining unauthorized access to sensitive information when httpd is deployed behind a reverse proxy.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 9.3 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Changed | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | None | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N
Understanding the Weakness (CWE)
Integrity,Non-Repudiation,Access Control
Technical Impact: Unexpected State; Hide Activities; Bypass Protection Mechanism
An attacker could create HTTP messages to exploit a number of weaknesses including 1) the message can trick the web server to associate a URL with another URL's webpage and caching the contents of the webpage (web cache poisoning attack), 2) the message can be structured to bypass the firewall protection mechanisms and gain unauthorized access to a web application, and 3) the message can invoke a script or a page that returns client credentials (similar to a Cross Site Scripting attack).
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
