CVE-2026-1525
Description
A flaw was found in undici, a Node.js HTTP/1.1 client. A remote attacker could exploit this vulnerability by sending HTTP/1.1 requests that include duplicate Content-Length headers with different casing (e.g., "Content-Length" and "content-length"). This can lead to HTTP Request Smuggling, a technique where an attacker sends an ambiguous request that is interpreted differently by a proxy and a backend server. Successful exploitation could result in unauthorized access, cache poisoning, or credential hijacking. It may also cause a Denial of Service (DoS) if strict HTTP parsers reject the malformed requests.
Statement
Moderate impact. A flaw in the undici Node.js HTTP/1.1 client allows for HTTP Request Smuggling or Denial of Service. This can occur in Red Hat products that use undici and process HTTP requests where user-controlled header names are not case-normalized, or headers are passed as flat arrays.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.3 | 9.8 | 6.5 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | Low | High | None |
| Integrity Impact | Low | High | Low |
| Availability Impact | Low | High | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
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).
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