Fission: SanitizeFilePath lexical HasPrefix bypass permits sibling-directory escape
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| fission | fission | before 1.25.0 | 1.25.0 | Patch available | CNA |
| — | github.com/fission/fission (Go) | before 1.25.0 | 1.25.0 | Patch available | GHSA-r5jh-q2mw-gcx4 |
- fission Vendorfission Affected before 1.25.0 Fixed in 1.25.0 Patch available CNA
- github.com/fission/fission (Go) Vendor— Affected before 1.25.0 Fixed in 1.25.0 Patch available GHSA-r5jh-q2mw-gcx4
Remediation
- Fix · CNA fission (fission) Fixed in 1.25.0
- Fix · GHSA-r5jh-q2mw-gcx4 github.com/fission/fission (Go) Fixed in 1.25.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-50568
- 2026-10-03 Alias added: GHSA-r5jh-q2mw-gcx4
References
Other 7
- 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
- https://github.com/fission/fission/commit/5aac6f0bcdf840e28f3f06c846ca7ae1866b3957
- https://github.com/fission/fission/commit/8298e33ea7457702f893eae11077987cf905edb4
- https://github.com/fission/fission
More fission vulnerabilities
- TI-2026-34271 Improper access control in fission CVSS 3.1CRITICAL 9.8
- TI-2026-34273 Improper privilege management in fission CVSS 4.0HIGH 8.7
- TI-2026-37288 Fission: Environment Runtime.Container and Builder.Container SecurityContext bypass allows privileged pod creation CVSS 3.1CRITICAL 9.9
- TI-2026-37286 Fission Environment CRD podspec passthrough enables hostPID/hostNetwork/privileged pods, node escape CVSS 3.1CRITICAL 9.9
- TI-2026-37285 Fission Container Executor Function PodSpec Injection Leading to Node Escape CVSS 3.1CRITICAL 9.9
- TI-2026-37268 Fission Environment CRD PodSpec Injection Leading to Node Escape and Cluster Takeover CVSS 3.1CRITICAL 9.9
Sources
- CVE-2026-50568 · CVE Program
- CVE-2026-50568 · NVD
- FIRST EPSS
- GHSA-r5jh-q2mw-gcx4 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences