CVE-2026-40561CWE-444

Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence

Medium · published May 3, 2026

CVSS v3.1
5.3
EPSS
0%
Percentile
36.6
In the wild
Unconfirmed
What it is

Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence.

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.

An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00433 · 36.6th percentile
Weakness
CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Published
2026-05-03T00:57Z
EPSS history
Timeline
  • 03 MAY 00:57Z
    Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence
    cvelistv5