# Youki: If /proc and /sys in the rootfs are symbolic links, they can potentially be exploited to gain access to the host root filesystem.

Advisory record · `GHSA-j26p-6wx7-f3pw`

- **Identifiers:** `GHSA-j26p-6wx7-f3pw` · `CVE-2025-54867`
- **State:** Confirmed
- **Severity:** CVSS 7.0 High
- **Critical:** No
- **Weakness (CWE):** [CWE-61](https://cwe.mitre.org/data/definitions/61.html)
- **Tags:** [CWE-61](https://agentprime.io/advisories/tag/cwe-61.md)
- **Published:** 14 Aug 2025
- **Updated:** 14 Aug 2025
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 14 Aug 2025, 16:39 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `youki` (crates.io): affected `<0.5.5`; fixed in `0.5.5`

## Machine-written summary

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

> Youki versions before 0.5.5 do not reject a container rootfs where /proc or /sys is a symbolic link, unlike runc, so such a container is created when it should be refused. An attacker who can supply or control the rootfs could potentially use the symlinked mount points to reach the host root filesystem. Upgrade youki to 0.5.5 or later. The source gives few details on the exact exploitation steps.

Written 8 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0019, the 9th percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 15:19 UTC: First seen by agentprime
- 31 Oct 2026, 15:19 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-j26p-6wx7-f3pw)

## Sources

- [GitHub Advisory Database: GHSA-j26p-6wx7-f3pw](https://github.com/advisories/GHSA-j26p-6wx7-f3pw)
- [OSV: GHSA-j26p-6wx7-f3pw](https://osv.dev/vulnerability/GHSA-j26p-6wx7-f3pw)
- <https://github.com/youki-dev/youki/security/advisories/GHSA-j26p-6wx7-f3pw>
- <https://nvd.nist.gov/vuln/detail/CVE-2025-54867>
- <https://github.com/youki-dev/youki/commit/0d9b4f2aa5ceaf988f3eb568711d2acf0a4ace37>
- <https://github.com/youki-dev/youki>
- <https://github.com/youki-dev/youki/releases/tag/v0.5.5>

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-j26p-6wx7-f3pw>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-j26p-6wx7-f3pw/>. Everything for agents: <https://agentprime.io/llms.txt>.