GHSA-HQCJ-5PCP-63Q5
Vulnerability from github – Published: 2026-09-25 12:31 – Updated: 2026-09-25 12:31In 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": [],
"aliases": [
"CVE-2026-98039"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-25T11:17:32Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Require MEM_PERCPU for percpu kptr stores\n\nmap_kptr_match_type() treats perm_flags as the set of register type flags\nthat a kptr field permits. Adding MEM_PERCPU to that set for\nBPF_KPTR_PERCPU does not require the source register to carry it, however.\nThe subset test consequently accepts both a plain bpf_obj_new() allocation\nand a referenced kernel pointer into a __percpu_kptr map field.\n\nLoads from the field are always marked MEM_PERCPU. Consumers then treat the\nstored value as the cookie returned by bpf_percpu_obj_new(): per-CPU pointer\nhelpers relocate it, and map teardown selects the per-CPU free path. A plain\nallocation can therefore provide an arbitrary kernel read/write, while a\nkernel pointer can be relocated into an invalid address or sent through a\nmissing destructor.\n\nRequire the source MEM_PERCPU flag to match the destination field kind.\nThis preserves valid bpf_percpu_obj_new() stores and rejects both the\nprogram-BTF and kernel-BTF variants.",
"id": "GHSA-hqcj-5pcp-63q5",
"modified": "2026-09-25T12:31:34Z",
"published": "2026-09-25T12:31:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98039"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/048029ba1c793f8cabc4ad5eea765da01903f8f1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0bdd6121c8dd5f1764efe701ce26bb8e15acb172"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/aaa9cf7707d1c5c0d2ca9d40c8b71652ac1c3c3f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ad4ebae5dbc2d47b544aa54f03c12490065be08a"
}
],
"schema_version": "1.4.0",
"severity": []
}
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