CVE-2026-1525

216.73.216.133

· Published 12/03/2026 20:16 · Modified 12/03/2026 21:07

Labels: CVE-2026-1525 2026-03-12 CVE-2026-1525 CWE-444 ce714d77-add3-4f53-aff5-83d477b104bb

Essential information

Published: 12/03/2026 20:16
Modified: 12/03/2026 21:07
Author: —
Creator: —
CVSS: 6.5 MEDIUM (v3.1)
CISA KEV: No
CWE: —
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

CVSS metrics

Description

Undici allows duplicate HTTP Content-Length headers when they are provided in an array with case-variant names (e.g., Content-Length and content-length). This produces malformed HTTP/1.1 requests with multiple conflicting Content-Length values on the wire. Who is impacted: * Applications using undici.request(), undici.Client, or similar low-level APIs with headers passed as flat arrays * Applications that accept user-controlled header names without case-normalization Potential consequences: * Denial of Service: Strict HTTP parsers (proxies, servers) will reject requests with duplicate Content-Length headers (400 Bad Request) * HTTP Request Smuggling: In deployments where an intermediary and backend interpret duplicate headers inconsistently (e.g., one uses the first value, the other uses the last), this can enable request smuggling attacks leading to ACL bypass, cache poisoning, or credential hijacking

NVD status

Status: Awaiting Analysis — CVE has been recently published to the CVE List and has been received by the NVD.
Source: ce714d77-add3-4f53-aff5-83d477b104bb
NVD: View on NVD

Affected products (CPE)

Product	CPE
undici / undici	`cpe:2.3:a:undici:undici::::::::`