Bug 2439039 (CVE-2026-26157)

Summary: CVE-2026-26157 busybox: BusyBox: Arbitrary file overwrite and potential code execution via incomplete path sanitization
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: adudiak, aprice, caswilli, dfreiber, drow, jburrell, jsamir, kaycoth, kshier, oezr, stcannon, teagle, vkumar, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in BusyBox. Incomplete path sanitization in its archive extraction utilities allows an attacker to craft malicious archives that when extracted, and under specific conditions, may write to files outside the intended directory. This can lead to arbitrary file overwrite, potentially enabling code execution through the modification of sensitive system files.
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Clone Of: Environment:
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2439044, 2439045, 2439046    
Bug Blocks:    

Description OSIDB Bzimport 2026-02-11 18:09:04 UTC
Affects: BusyBox v1.36.1 and v1.37.0 (likely affects earlier versions too)
CVSS: 8.6 (HIGH)
Component: strip_unsafe_prefix() function in archive extraction utilities
          (tar, unzip, rpm, ar, dpkg)

Description:
Incomplete path sanitization fails to detect trailing ".." components in
filenames (e.g., "logs/data/.."), allowing files to be written outside the
intended extraction directory when the current working directory matches
the target location. An attacker can craft malicious archives that
overwrite arbitrary files within the extraction directory scope.

Impact:
Arbitrary file overwrite, potential code execution through modification of
shell configuration files, cron jobs, or other sensitive files.