Kata guest escape: runtime-rs guest-root to host-root escape via virtiofs

Exploitation

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

CVSS 4.0

8.4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:P · score source

EPSS

• CVE-2026-47243: 0.20% estimated exploitation activity in the next 30 days; percentile 9.38 (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.

Summary In the runtime-rs standalone virtio-fs path, verified here with QEMU (and verified with Cloud Hypervisor too), Kata Containers runs host virtiofsd as root with: If an attacker has root-equivalent execution inside the Kata guest VM, they can send raw FUSE requests directly to the host virtiofsd. With the tested runtime-rs virtio-fs configuration, a raw FUSESYMLINK request whose new symlink name is an absolute host path is honored outside the virtio-fs shared directory. This lets guest root create host-root owned symlinks in sensitive host paths. The PoC created here will create symlinks in the host /etc/cron.d directory, causing host cron to execute a guest-controlled payload as host root. Impact: guest root can execute code as host root. Affected configuration The verified host used: Pinned upstream references, using Kata Containers main commit 2ffd1538a296cff93a357bfba0dfca747480a1f8: - runtime-rs standalone virtio-fs adds --sandbox none --seccomp none to the virtiofsd…

Published by the source

27 May 2026, 22:50 UTC

Last modified by the source

27 May 2026, 22:50 UTC

Source last checked

26 Oct 2026, 15:22 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-2gv2-cffp-j227

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# Patch Next advisory brief: CVE-2026-47243

Advisory: Kata guest escape: runtime-rs guest-root to host-root escape via virtiofs
IDs: CVE-2026-47243, GHSA-2gv2-cffp-j227
Record: https://patchnext.com/advisories/cve-2026-47243 (revision 1, source checked 26 Oct 2026, 15:22 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/kata-containers/kata-containers 0.0.0-20260519062212-ffa59ce3aa78. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/kata-containers/kata-containers: affected < 0.0.0-20260519062212-ffa59ce3aa78; fixed in 0.0.0-20260519062212-ffa59ce3aa78

## Suggested inspection (read-only)
- Go github.com/kata-containers/kata-containers: 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/kata-containers/kata-containers.
- 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://github.com/advisories/GHSA-2gv2-cffp-j227 (GitHub-reviewed advisory GHSA-2gv2-cffp-j227 lists affected ranges: Go github.com/kata-containers/kata-containers >=0 <0.0.0-20260519062212-ffa59ce3aa78)

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