CVE-2026-98039
UnknownSummary
In the Linux kernel, the BPF verifier did not require the MEM_PERCPU flag for stores to percpu kptr fields, accepting both plain bpf_obj_new() allocations and kernel pointers. This could lead to arbitrary kernel read/write or invalid address relocation.
Risk Assessment
Arbitrary kernel memory read/write is possible, posing a serious threat to confidentiality, integrity, and availability.
Recommendation
Update the Linux kernel to a version containing the fix that requires the source MEM_PERCPU flag to match the destination field kind.
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Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: bpf: Require MEM_PERCPU for percpu kptr stores map_kptr_match_type() treats perm_flags as the set of register type flags that a kptr field permits. Adding MEM_PERCPU to that set for BPF_KPTR_PERCPU does not require the source register to carry it, however. The subset test consequently accepts both a plain bpf_obj_new() allocation and a referenced kernel pointer into a __percpu_kptr map field. Loads from the field are always marked MEM_PERCPU. Consumers then treat the stored value as the cookie returned by bpf_percpu_obj_new(): per-CPU pointer helpers relocate it, and map teardown selects the per-CPU free path. A plain allocation can therefore provide an arbitrary kernel read/write, while a kernel pointer can be relocated into an invalid address or sent through a missing destructor. Require the source MEM_PERCPU flag to match the destination field kind. This preserves valid bpf_percpu_obj_new() stores and rejects both the program-BTF and kernel-BTF variants.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

