Bug 2536778 (CVE-2026-93148)

Summary: CVE-2026-93148 kernel: bpf: Reject MEM_ALLOC BTF accesses past object bounds
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 Berkeley Packet Filter (BPF) component. This vulnerability arises from incorrect boundary checks during BPF Type Format (BTF) struct walks for memory-allocated objects. Specifically, the system fails to reject accesses that extend beyond the allocated object's static size before applying flexible-array relaxations. This out-of-bounds access could potentially lead to memory corruption.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-09-17 19:32:51 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bpf: Reject MEM_ALLOC BTF accesses past object bounds

BTF struct walks relax the struct-size check for accesses through a
trailing flexible array. That is valid for ordinary BTF type walking, but
PTR_TO_BTF_ID | MEM_ALLOC values point to objects allocated with the static
BTF type size.

When walking a MEM_ALLOC object, reject the access before applying the
flexible-array relaxation if the access range extends past the struct size.
Apply the same policy to struct ID matching so kfunc and kptr type checks
do not walk past the allocated object bounds either.
Comment 1 gkamathe 2026-09-18 20:41:19 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93148.mbox