Vulnerability · Published Oct 30, 2026 · Assigned by CPANSec
CVE-2026-116127Starlet versions before 0.33 for Perl send a body in responses to HEAD requests, corrupting the next response on a persistent or pipelined connection
Unrated
In plain English
A security flaw in Starlet. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | starlet | no fix listed | DEBIAN-CVE-2026-116127 |
| Debian:13 | starlet | no fix listed | DEBIAN-CVE-2026-116127 |
| Debian:14 | starlet | 0.33-1 | DEBIAN-CVE-2026-116127 |
| Ubuntu:22.04:LTS | starlet | no fix listed | UBUNTU-CVE-2026-116127 |
| Ubuntu:24.04:LTS | starlet | no fix listed | UBUNTU-CVE-2026-116127 |
| Ubuntu:26.04:LTS | starlet | no fix listed | UBUNTU-CVE-2026-116127 |
| Ubuntu:26.10 | starlet | no fix listed | UBUNTU-CVE-2026-116127 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Starlet | 0 – before 0.33 |
Weakness: CWE-444