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

Status: published. Published: 2026-02-11. Updated: 2026-11-04.

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.

## Remediation

- workaround: As a prevention measure, avoid extracting tar archives from untrusted sources using BusyBox, especially when operating with elevated privileges. If processing untrusted archives is unavoidable, ensure that the extraction process is performed within a strictly sandboxed environment with minimal permissions. This operational control reduces the risk of arbitrary file modification and privilege escalation. (source: CNA: redhat)
- fix: RHSA-2026:13831: Red Hat Hardened Images (source: ADP: redhat-SADP)
- workaround: As a prevention measure, avoid extracting tar archives from untrusted sources using BusyBox, especially when operating with elevated privileges. If processing untrusted archives is unavoidable, ensure that the extraction process is performed within a strictly sandboxed environment with minimal permissions. This operational control reduces the risk of arbitrary file modification and privilege escalation. (source: ADP: redhat-SADP)

## Affected products and versions

- Red Hat / Red Hat Hardened Images (busybox-main): ≥ 1.37.0-7.2.hum1; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (busybox): Version range not reported. Source: CNA: redhat
- Siemens / RUGGEDCOM RST2428P: ≥ 0; < V4.0 (affected, custom). Source: ADP: siemens-SADP
- Red Hat / Red Hat Hardened Images (busybox-main): ≥ 1.37.0-7.2.hum1; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 6 (busybox): Version range not reported. Source: ADP: redhat-SADP

## Severity and prioritization

- CVSS 3.1: 7 (high); CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H; source: CNA: redhat

- CVSS 3.1: 7 (high); CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H; source: ADP: redhat-SADP

- CVSS 3.1: 7 (high); CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H; source: NVD: secalert@redhat.com

- CVSS 3.1: 7 (high); CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H; source: NVD: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

- CISA KEV: No listing in collected sources

- EPSS: 0.19% as of 2026-11-04; percentile 9.04%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-73

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2026:13831 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-26158 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2439040 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://git.busybox.net/busybox/commit/archival?id=3fb6b31c716669e12f75a2accd31bb7685b1a1cb (CNA: redhat)

- https://cert-portal.siemens.com/productcert/html/ssa-253495.html (ADP: siemens-SADP)

- https://access.redhat.com/security/cve/CVE-2026-26158 (ADP: redhat-SADP; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2439040 (ADP: redhat-SADP; issue-tracking, x_refsource_REDHAT)

- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-26158.json (ADP: redhat-SADP; x_sadp-csaf-vex)

- https://access.redhat.com/errata/RHSA-2026:13831 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:13831 (secalert@redhat.com)

- https://access.redhat.com/security/cve/CVE-2026-26158 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2439040 (secalert@redhat.com)

- https://git.busybox.net/busybox/commit/archival?id=3fb6b31c716669e12f75a2accd31bb7685b1a1cb (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:13831 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/security/cve/CVE-2026-26158 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://bugzilla.redhat.com/show_bug.cgi?id=2439040 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://cert-portal.siemens.com/productcert/html/ssa-253495.html (0b142b55-0307-4c5a-b3c9-f314f3fb7c5e)

- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-26158.json (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-26158; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-26158; retrieved 2026-11-05; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-26158; retrieved 2026-11-04; source updated Not reported

Revision: f13cd1e9895f27e593b562b6eda60c37ff1ae98a761827f2e6c9aeb05123582d

Canonical: https://y2.dev/cve/CVE-2026-26158

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