Fission: SanitizeFilePath lexical HasPrefix bypass permits sibling-directory escape

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

3.6 · CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

EPSS

• CVE-2026-50568: 0.11% estimated exploitation activity in the next 30 days; percentile 1.55 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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. Affected - Project: github.com/fission/fission - Versions: all versions through v1.24.0 with SanitizeFilePath in the tree - Audited commit: 647c141 - Component: pkg/utils/utils.go:SanitizeFilePath - Callers: pkg/builder/builder.go:157,164,208, pkg/fetcher/fetcher.go:296,311,450,496,565,571…

Published by the source

28 Jul 2026, 20:18 UTC

Last modified by the source

18 Aug 2026, 15:00 UTC

Source last checked

26 Oct 2026, 15:27 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-r5jh-q2mw-gcx4

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6130

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-r5jh-q2mw-gcx4

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# Patch Next advisory brief: CVE-2026-50568

Advisory: Fission: SanitizeFilePath lexical HasPrefix bypass permits sibling-directory escape
IDs: CVE-2026-50568, GHSA-r5jh-q2mw-gcx4
Record: https://patchnext.com/advisories/cve-2026-50568 (revision 3, source checked 26 Oct 2026, 15:27 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/fission/fission 1.25.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/fission/fission: affected <= 1.24.0; fixed in 1.25.0

## Suggested inspection (read-only)
- Go github.com/fission/fission: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/fission/fission.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-r5jh-q2mw-gcx4 (OSV record GHSA-r5jh-q2mw-gcx4 lists affected ranges: Go github.com/fission/fission >=0 <1.25.0 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6130 (OSV record GO-2026-6130 lists affected ranges: Go github.com/fission/fission >=0 <1.25.0 (fixed))
- Verified: https://github.com/advisories/GHSA-r5jh-q2mw-gcx4 (GitHub-reviewed advisory GHSA-r5jh-q2mw-gcx4 lists affected ranges: Go github.com/fission/fission >=0 <=1.24.0)

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