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CVE-2026-40560

34
FAUCET Score

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 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.

First published: Apr 28, 2026Last modified: Apr 29, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 0.4018CPE matchmatch criteria
cpe:2.3:a:miyagawa:starman:*:*:*:*:*:perl:*:*
>= 0, < 0.4018CPE match
cpe:2.3:a:miyagawa:starman:*:*:*:*:*:perl:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.49%
Probability of exploitation in next 30 days
EPSS Percentile
39.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0049 is in the 17th percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

datatracker.ietf.org / doc/html/rfc7230
Third Party Advisory
github.com / miyagawa/Starman/commit/ced205f0805027e9d9c0731f8c40b104220604ed.patch
PatchThird Party Advisory
metacpan.org / release/MIYAGAWA/Starman-0.4018/changes
ProductRelease Notes
openwall.com / lists/oss-security/2026/04/29/1
Mailing ListThird Party Advisory