CVE-2026-40561

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

03/05/2026

Last modified:

06/05/2026

Description

Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence.<br /> <br /> Starlet incorrectly prioritizes "Content-Length" over "Transfer-Encoding: chunked" when both headers are present in an HTTP request. Per RFC 7230 3.3.3, Transfer-Encoding must take precedence.<br /> <br /> An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.30 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): Low
Availability (A): None