Bug 2536707 (CVE-2026-93146)

Summary: CVE-2026-93146 kernel: time/namespace: Validate nanosecond field in proc_timens_set_offset()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's time namespace handling. The `proc_timens_set_offset()` function does not properly validate the nanosecond field (`tv_nsec`) when setting time offsets. This oversight allows for invalid nanosecond values to be used in time calculations, which can lead to incorrect system time or other unexpected behavior.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-17 19:10:39 UTC 
In the Linux kernel, the following vulnerability has been resolved:

time/namespace: Validate nanosecond field in proc_timens_set_offset()

The function validates tv_sec to be within [-KTIME_SEC_MAX, KTIME_SEC_MAX]
but never validates that tv_nsec is within the valid range of
[0, NSEC_PER_SEC-1] before using it in timespec64_add().

timespec64_add() expects both timespec64 structures to have normalized
values with tv_nsec in the range [0, 999999999]. If off->val.tv_nsec
contains invalid values (negative or >= NSEC_PER_SEC), it could lead to
incorrect calculations or unexpected behavior.

Add validation to ensure tv_nsec is within the valid range before
performing the addition.
Comment 1 gkamathe 2026-09-18 20:22:56 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93146.mbox