What is CVE-2026-40560?

CVE-2026-40560 is a high-severity vulnerability in Miyagawa Starman, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 7.5/10. Published 2026-04-29.

How severe is CVE-2026-40560?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Miyagawa Starman

CVE-2026-40560

Starman versions before 0.4018 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Starman incorrectly prioritizes "Content-Length" over "Transfer-Encoding: chunked" when both headers are present in an HTTP request. Per…

Vulnerability class: HTTP Request Smuggling

EPSS: 0.000 (3.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

Affected products

Miyagawa Starman — versions 0

Weakness classification (CWE)

CWE-444 — Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling)

References

9b29abf9-4ab0-4765-b253-1875cd9b441e (Patch, Third Party Advisory, patch)
9b29abf9-4ab0-4765-b253-1875cd9b441e (release-notes, Product, Release Notes)
9b29abf9-4ab0-4765-b253-1875cd9b441e (Third Party Advisory)
af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2026-40560?: CVE-2026-40560 is a high-severity vulnerability in Miyagawa Starman, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 7.5/10. Published 2026-04-29.
How severe is CVE-2026-40560?: High severity. CVSS v3 base score is 7.5 out of 10.