BusyBox ar archive handler path traversal

Summaryinfo

A vulnerability was found in BusyBox. It has been classified as problematic. Affected is an unknown function of the component ar archive handler. Performing a manipulation results in path traversal. This vulnerability is identified as CVE-2026-90954. The attack is only possible with local access. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, was found in BusyBox (unknown version). This affects an unknown code block of the component ar archive handler. The manipulation with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

A flaw was found in BusyBox's dpkg-deb archive extraction. The ar archive handler flushes deferred symlinks after each archive member, unlike the tar, cpio, and unzip handlers which flush once after the last member. A specially crafted .deb archive with two data.tar members can exploit this ordering: the first member declares a symlink pointing to an absolute path (e.g., '/'), which is deferred as unsafe but flushed after the first member. The second member declares a regular file whose path traverses the now-live symlink, resulting in a file being written outside the intended extraction directory. This could allow an attacker to write arbitrary files to arbitrary locations when a user extracts a crafted .deb package.

The advisory is shared at access.redhat.com. This vulnerability is uniquely identified as CVE-2026-90954 since 09/14/2026. The exploitability is told to be easy. An attack has to be approached locally. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1006 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Name

• BusyBox

License

• open-source

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

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