Bug 2535135 (CVE-2026-89799)

Summary: CVE-2026-89799 kernel: bpf: Disable preemption in bpf_get_stackid
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: 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
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) component. Specifically, within the `bpf_get_stackid` function, preemption was not properly disabled when calling `get_perf_callchain` and accessing its trace entries buffer. This oversight could lead to a race condition, where multiple operations might interfere with each other. Such an issue could result in system instability, unintended information disclosure, or a denial of service (DoS) to the affected system.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-16 10:55:25 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bpf: Disable preemption in bpf_get_stackid

The get_perf_callchain call needs disabled preemption plus we need
it disabled as long as we access its returned trace entries buffer.

Note the bpf_get_stackid_pe function is executed already with
preemption disabled.
Comment 1 Mauro Matteo Cascella 2026-09-21 13:28:16 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89799.mbox