---
id: CVE-2026-116127
title: >-
  Starlet versions before 0.33 for Perl send a body in responses to HEAD
  requests, corrupting the next response on a persistent or pipelined connection
summary: >-
  Starlet versions before 0.33 for Perl send a body in responses to HEAD
  requests, corrupting the next response on a persistent or pipelined
  connection.


  The request method is not passed to the response writer, so whatever body the
  applica…
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H'
cvssSource: adp
cwe:
  - CWE-444
product: Starlet
affected:
  - Starlet < 0.33
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-11-06T16:34:53.882732Z'
published: '2026-10-30'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:35:22.422Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-116127'
references:
  - url: >-
      https://github.com/kazuho/Starlet/commit/859e0c9572cdbed4bb45706d3957b3c025dc0ede.patch
  - url: 'https://metacpan.org/release/KAZUHO/Starlet-0.33/changes'
tags:
  - cve.org
epss: 0.00322
epssPercentile: 0.25383
ingestedAt: '2026-11-05T16:07:30.204Z'
---

## Overview

Starlet versions before 0.33 for Perl send a body in responses to HEAD requests, corrupting the next response on a persistent or pipelined connection.

The request method is not passed to the response writer, so whatever body the application returns for a HEAD request is sent. With Plack::Middleware::Head the body is empty, but an HTTP/1.1 response without a Content-Length header still gets the chunked encoding terminator. Responses with status 204 or 304 are also sent with their body.

Pipelined GET and HEAD requests keep the connection open even when keep-alive is disabled, which is the default. A client or proxy reading the connection takes the extra bytes as the start of the next response, which may desynchronize a proxy that shares the connection across clients.

## Affected

- `Starlet < 0.33`

## Remediation

Upgrade to Starlet 0.33 or later.