Bug 2518108 (CVE-2026-54552)

Summary: CVE-2026-54552 sh: sh: Incomplete privilege drop allows child processes to retain privileged group access.
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: aprice, dkeler, gtanzill, jbuscemi, jsamir, oezr, suppawar, thason
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in sh, a Python library for process launching. When sh runs from an elevated process and launches a command with the `_uid` option set to an unprivileged user, the child process may retain the parent process's supplementary groups. This incomplete privilege drop can allow the child process to retain access to files or resources granted to privileged groups, leading to unauthorized access and potential privilege escalation.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-18 17:54:06 UTC 
sh provides Python process launching. Prior to 2.2.4, the _uid option in sh.py performs an incomplete privilege drop on Linux and Unix-like systems. When sh runs from an elevated process and launches a command with _uid set to an unprivileged user, the child changes its UID but can retain the parent process's supplementary groups because the privilege-drop sequence does not fully establish the target user's UID, primary GID, and supplementary groups. The child can therefore retain access to files or resources granted to privileged groups such as root, docker, disk, shadow, or sudo, violating the expected _uid privilege boundary. This issue is fixed in version 2.2.4.