VulnerabilityPublished 25 Oct 2026

CVE-2026-115823: Starman (Perl module) · HTTP Request Smuggling

Affects Starman (Perl module)Source CVE Database V5

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Not known to be exploited : upgrade to 0.4019 when convenient.

Data as of 29 Oct 2026, 19:15 UTC

Severity

Medium

Rated Medium by the CNA (CPANSec) · CVSS not yet scored by NVD

Thin evidence

One scorer or none

EPSS: 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.4019

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-4q75-5w63-6hx7

What to do

Upgrade Starman (Perl module) to 0.4019.

Affected software

Product	Affected	Fixed in
Starman	Affected <0.4019	Fixed in 0.4019
CPANStarman`pkg:cpan/Starman`Other threats	Affected <0.4019	Fixed in 0.4019

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, avoid using vulnerable versions of Starman in environments where keep-alive or pipelined HTTP connections are proxied or reused.

Description

Starman versions before 0.4019 for Perl send response bodies for HEAD requests, desynchronizing responses on keep-alive connections. For a HEAD request Starman omits chunked framing but still writes the body returned by the application, on both the array and streaming response paths. Responses with a 1xx, 204 or 304 status also carry the body. On a keep-alive or pipelined connection the client reads those bytes as the start of the next response. A front-end proxy that reuses upstream connections may then pair responses with the wrong requests.

Impact

The vulnerability can cause response desynchronization on persistent connections, leading to front-end proxies or clients associating responses with the wrong requests. This may result in incorrect data being delivered to clients or proxies, potentially causing information leakage or other unintended behaviors in HTTP communication chains.

Summary

CVE-2026-115823 describes a vulnerability in Starman (a Perl web server) versions prior to 0.4019 where response bodies are sent for HTTP HEAD requests despite the omission of chunked framing. Additionally, responses with status codes 1xx, 204, or 304 also include bodies incorrectly. This behavior causes desynchronization on keep-alive or pipelined connections, allowing clients or front-end proxies that reuse upstream connections to misinterpret response boundaries, potentially pairing responses with incorrect requests. This is classified under CWE-444, indicating inconsistent interpretation of HTTP requests, commonly known as HTTP request/response smuggling.

CWE-444Inconsistent Interpretation of HTTP Requests (HTTP Request Smuggling) (opens in a new tab)
Base weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
Implementation
Use a web server that employs a strict HTTP parsing procedure, such as Apache.
Implementation
Use only SSL communication.
Implementation
Terminate the client session after each request.
OWASP Cheat Sheets
REST Assessment (opens in a new tab)
REST Security (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
Secure Design Principles (opens in a new tab)
OWASP ASVS 4.0.3
V13.2.5 (opens in a new tab)
Attack patterns
HTTP Response Smuggling (opens in a new tab)
HTTP Request Smuggling (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 17:11 UTC

WeaknessesCWE-444

Technical details

References

Community reviews

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