CVE-2026-108119
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.
Statement
This vulnerability is rated as having a Moderate impact because successful exploitation requires an attacker to convince a user or automated process to extract an untrusted archive, combined with non-trivial filesystem or extraction directory reuse constraints. The risk is further confined to scenarios where the BusyBox implementation of tar processes malicious archives with elevated privileges.
Mitigation
Avoid extracting tar archives from untrusted sources using busybox, especially with elevated privileges or into a directory that will be reused for a subsequent extraction. If untrusted archives must be processed, extract into a freshly created, isolated directory with minimal privileges on a single filesystem boundary and discard it (including any links left on disk) after each extraction.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.3 | N/A | 6.3 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H
Acknowledgements
Red Hat would like to thank TAE3 for reporting this issue.
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