# Fission: SanitizeFilePath lexical HasPrefix bypass permits sibling-directory escape

Advisory record · `GHSA-r5jh-q2mw-gcx4`

- **Identifiers:** `GHSA-r5jh-q2mw-gcx4` · `CVE-2026-50568` · `GO-2026-6130`
- **State:** Confirmed
- **Severity:** CVSS 3.6 Low
- **Critical:** No
- **Weakness (CWE):** [CWE-41](https://cwe.mitre.org/data/definitions/41.html)
- **Tags:** [CWE-41](https://agentprime.io/advisories/tag/cwe-41.md)
- **Published:** 28 Jul 2026
- **Updated:** 18 Aug 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 28 Jul 2026, 20:18 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `github.com/fission/fission` (Go): affected `<1.25.0`; fixed in `1.25.0`

## Machine-written summary

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

> Fission (github.com/fission/fission) versions before 1.25.0 contain a path check in SanitizeFilePath that only does a plain string-prefix comparison, so a sibling directory whose name begins with the safe directory's name is accepted. An attacker who can create or control such a sibling directory on the fetcher or builder's shared volume could read or write files outside the intended directory. Upgrade to version 1.25.0, which removes the vulnerable function.

Written 6 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0011, the 1st percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:50 UTC: First seen by agentprime
- 31 Oct 2026, 14:50 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-r5jh-q2mw-gcx4)

## Sources

- [GitHub Advisory Database: GHSA-r5jh-q2mw-gcx4](https://github.com/advisories/GHSA-r5jh-q2mw-gcx4)
- [OSV: GHSA-r5jh-q2mw-gcx4](https://osv.dev/vulnerability/GHSA-r5jh-q2mw-gcx4)
- <https://github.com/fission/fission/security/advisories/GHSA-r5jh-q2mw-gcx4>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-50568>
- <https://github.com/fission/fission/pull/3445>
- <https://github.com/fission/fission/pull/3446>
- <https://github.com/fission/fission/commit/5aac6f0bcdf840e28f3f06c846ca7ae1866b3957>
- <https://github.com/fission/fission/commit/8298e33ea7457702f893eae11077987cf905edb4>
- <https://github.com/fission/fission>
- <https://github.com/fission/fission/releases/tag/v1.25.0>

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-r5jh-q2mw-gcx4>, 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-r5jh-q2mw-gcx4/>. Everything for agents: <https://agentprime.io/llms.txt>.