# Skipper is vulnerable to arbitrary code execution through lua filters in github.com/zalando/skipper

Advisory record · `GHSA-cc8m-98fm-rc9g`

- **Identifiers:** `GHSA-cc8m-98fm-rc9g` · `CVE-2026-23742` · `GO-2026-4327`
- **State:** Confirmed
- **Severity:** CVSS 8.8 High
- **Critical:** No
- **Weakness (CWE):** [CWE-94](https://cwe.mitre.org/data/definitions/94.html) · [CWE-250](https://cwe.mitre.org/data/definitions/250.html) · [CWE-522](https://cwe.mitre.org/data/definitions/522.html)
- **Tags:** [Code injection](https://agentprime.io/advisories/tag/code-injection.md) · [Privilege escalation](https://agentprime.io/advisories/tag/privilege-escalation.md) · [Hard-coded credentials](https://agentprime.io/advisories/tag/hard-coded-credentials.md)
- **Published:** 3 Feb 2026
- **Updated:** 3 Mar 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 3 Feb 2026, 20:37 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `github.com/zalando/skipper` (Go): affected `<0.23.0`; fixed in `0.23.0`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Skipper, the github.com/zalando/skipper Go package, is vulnerable to arbitrary code execution through its Lua filters in versions before 0.23.0. The source gives few details about what an attacker needs to exploit it. Upgrade to version 0.23.0 or later.

Written 10 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.8 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0051, the 44th percentile, on 12 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 3 Feb 2026. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-cc8m-98fm-rc9g](https://github.com/advisories/GHSA-cc8m-98fm-rc9g)
- [OSV: GHSA-cc8m-98fm-rc9g](https://osv.dev/vulnerability/GHSA-cc8m-98fm-rc9g)
- <https://github.com/zalando/skipper/security/advisories/GHSA-cc8m-98fm-rc9g>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-23742>
- <https://github.com/zalando/skipper/commit/0b52894570773b29e2f3c571b94b4211ef8fa714>
- <https://github.com/zalando/skipper/releases/tag/v0.23.0>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-cc8m-98fm-rc9g>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-cc8m-98fm-rc9g/>. Everything for agents: <https://agentprime.io/llms.txt>.