CVE-2026-50567
Unarchive in pkg/utils/zip.go joined each archive entry name with the destination directory via filepath.Join and wrote the result without checking whether the resolved path stayed under the destination. A zip entry named
../../tmp/evil therefore landed at /tmp/evil. An attacker who could control a Package.Spec.Source.URL or Deployment.URL archive could induce the fetcher (running as the per-environment pod's fission-fetcher sidecar) to write
files anywhere that process could reach: into other tenants' /packages/<ns>/ directories, into mounted secret/config volumes, or into the fetcher's own binary.
Affected
- Project: github.com/fission/fission
- Versions: all up to and including v1.24.0
- Audited commit: 647c141
- Component: pkg/utils/zip.go (Unarchive)
- Configuration: default; triggered when the fetcher downloads and extracts a zip archive
Fix section (paste into the Fix / Patches field)
Fixed in v1.25.0 by:
- PR #3444 (commit 55704aca) — Unarchive now opens an os.Root on the destination, validates each
archive entry name (rejects absolute paths and .. traversal), and refuses symlink entries up front. The os.Root confines every mkdir / create to the destination in the kernel.
Regression coverage: TestUnarchiveZipSlip in pkg/utils/zip_test.go exercises parent-traversal, absolute-path, and symlink entries.
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Exploitation outlook
- Low exploitation risk0.30% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 22% of all EPSS-scored CVEs.
Advisory coverage (1)
External references
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