CVE-2026-50568Fission: SanitizeFilePath lexical HasPrefix bypass permits sibling-directory escape
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 3.6 LOW (v3.1, CNA)CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
- Weakness (CWE)
- CWE-41
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Jun 11, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
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