# 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.

> Cross-origin pages can probe any GET route via WebSocket handshakes to determine path existence, bypassing Origin checks in the Punk Perl library.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Oct 2026
- **Updated:** 6 Oct 2026
- **Also known as:** GHSA-cmh9-2wr3-4x64

## What is CVE-2026-104380?

CVE-2026-104380 is a medium-severity missing authorization vulnerability, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-1385 (Missing Origin Validation in WebSockets)

## Which versions are affected by CVE-2026-104380?


## How do I fix CVE-2026-104380?

No fix has been published for CVE-2026-104380 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-104380 being exploited?

There is no known exploitation of CVE-2026-104380 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104380 and fix it if it is affected.

What it is: CVE-2026-104380 is a medium-severity missing authorization vulnerability, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-104380 in the wild and no public exploit code.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-104380/ (Markdown: https://insights.sbomify.com/CVE-2026-104380/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104380
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104380
- OSV: https://osv.dev/vulnerability/CVE-2026-104380

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-104380/
Summaries are generated and may contain mistakes; the official description above is the record.