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CVE-2026-116127                                      CPAN Security Group
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         CVE ID:  CVE-2026-116127

   Distribution:  Starlet
       Versions:  before 0.33
       MetaCPAN:  https://metacpan.org/dist/Starlet
       VCS Repo:  https://github.com/kazuho/Starlet

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

Description
-----------
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.

Problem types
-------------
- CWE-444 Inconsistent Interpretation of HTTP Requests

Solutions
---------
Upgrade to Starlet 0.33 or later.

References
----------
https://github.com/kazuho/Starlet/commit/859e0c9572cdbed4bb45706d3957b3c025dc0ede.patch
https://metacpan.org/release/KAZUHO/Starlet-0.33/changes