CVE-2026-50568 PUBLISHED

Fission: SanitizeFilePath lexical HasPrefix bypass permits sibling-directory escape

Assigner: GitHub_M
Reserved: 04.06.2026 Published: 10.06.2026 Updated: 11.06.2026

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.

Metrics

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

Product Status

Vendor fission
Product fission
Versions
  • Version < 1.25.0 is affected

References

Problem Types

  • CWE-41: Improper Resolution of Path Equivalence CWE