# Root escape via symlink plus trailing slash in os

Advisory record · `GO-2026-4970`

- **Identifiers:** `GO-2026-4970` · `BIT-golang-2026-39822` · `CVE-2026-39822`
- **State:** Confirmed
- **Severity:** CVSS 7.8 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:** 7 Jul 2026
- **Updated:** 16 Sept 2026
- **Reviewed by a person:** No

Published by OSV at 7 Jul 2026, 21:34 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `stdlib` (Go): affected `<1.25.12 || >=1.26.0-0, <1.26.5 || >=1.27.0-0, <1.27.0-rc.2`; fixed in `1.25.12`, `1.26.5`, `1.27.0-rc.2`

## 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

- 7.8 High, CVSS 3.1: `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`, from ADP (CISA-ADP)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0023, the 14th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:13 UTC: First seen by agentprime
- 31 Oct 2026, 14:13 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GO-2026-4970)

## Sources

- [OSV: GO-2026-4970](https://osv.dev/vulnerability/GO-2026-4970)
- <https://groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc>
- <https://go.dev/cl/797880>

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/GO-2026-4970>, 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/GO-2026-4970/>. Everything for agents: <https://agentprime.io/llms.txt>.