Bug 2516880 (CVE-2026-74370)

Summary: CVE-2026-74370 kernel: liveupdate: fix TOCTOU race in luo_session_retrieve()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's liveupdate module. This vulnerability involves a Time-of-check to Time-of-use (TOCTOU) race condition within the `luo_session_retrieve()` function. A concurrent thread could release and free a session after it has been looked up but before a necessary mutex lock is acquired. This could lead to unpredictable behavior or a denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-15 06:38:18 UTC 
In the Linux kernel, the following vulnerability has been resolved:

liveupdate: fix TOCTOU race in luo_session_retrieve()

Extend the scope of the rwsem_read lock in luo_session_retrieve() to
overlap with the acquisition of the session mutex. This prevents a
concurrent thread from releasing and freeing the session between the
lookup and the mutex lock.
Comment 1 Keith Grant 2026-08-20 19:28:27 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081503-CVE-2026-74370-29f3@gregkh/T