Bug 2536306 (CVE-2026-90300)

Summary: CVE-2026-90300 kernel: bpf: Clear buf on error in __bpf_get_task_stack
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) subsystem. The `__bpf_get_task_stack` helper function, used by `bpf_get_task_stack` and `bpf_get_task_stack_sleepable`, fails to clear a buffer (`buf`) on error paths. This oversight can lead to non-deterministic buffer contents, potentially resulting in information disclosure when the buffer is subsequently used, for example, as a map key.
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Description OSIDB Bzimport 2026-09-17 17:18:10 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bpf: Clear buf on error in __bpf_get_task_stack

Both bpf_get_task_stack and bpf_get_task_stack_sleepable helpers that
use __bpf_get_task_stack have buf defined as ARG_PTR_TO_UNINIT_MEM
argument and we should initialize the buf on every return path.

Adding missing buf memset for __bpf_get_task_stack fail paths. This
provides deterministic buffer contents, which is useful when the buffer
is used directly as a map key.
Comment 1 gkamathe 2026-09-22 21:00:01 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90300.mbox