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CVE-2026-98039

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Last modified

CVE-2026-98039 is a vulnerability of currently unknown severity. 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.

Description

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.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 36d8bdf75a93190e5669b9d1d95994e13e15ba1d, < aaa9cf7707d1c5c0d2ca9d40c8b71652ac1c3c3f; >= 36d8bdf75a93190e5669b9d1d95994e13e15ba1d, < 0bdd6121c8dd5f1764efe701ce26bb8e15acb172; >= 36d8bdf75a93190e5669b9d1d95994e13e15ba1d, < ad4ebae5dbc2d47b544aa54f03c12490065be08a; >= 36d8bdf75a93190e5669b9d1d95994e13e15ba1d, < 048029ba1c793f8cabc4ad5eea765da01903f8f1
LinuxLinux6.7

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-98039?
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.
How severe is CVE-2026-98039?
Severity scoring for CVE-2026-98039 is pending analysis.
How do I fix CVE-2026-98039?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST