Vulnerability details
CVE-2026-64036
cgroup/rstat: validate cpu before css_rstat_cpu() access
Official description
In the Linux kernel, the following vulnerability has been resolved: cgroup/rstat: validate cpu before css_rstat_cpu() access css_rstat_updated() is exposed as a BPF kfunc and accepts a caller-provided cpu argument. The function uses cpu for per-cpu rstat lookups without checking whether it refers to a valid possible CPU. A BPF iter/cgroup program with CAP_BPF and CAP_PERFMON can pass an invalid cpu value. On an unfixed UBSCAN_BOUNDS test kernel, cpu == 0x7fffffff triggers: UBSAN: array-index-out-of-bounds in kernel/cgroup/rstat.c:31:9 index 2147483647 is out of range for type 'long unsigned int [64]' Call Trace: css_rstat_updated bpf_iter_run_prog cgroup_iter_seq_show bpf_seq_read Add cpu validation to the BPF-facing css_rstat_updated() kfunc and move the common implementation to __css_rstat_updated() for in-kernel callers.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.8High | 3.1 | CVEProject cvelistV5 (CNA) (Linux) | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| Linux | Linux | 6.1 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | a319185be9f5ad13c2a296d448ac52ffe45d194c ≤ v < b28b862b07257219755d0b0a7fbe5d23b7c9ea91 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | a319185be9f5ad13c2a296d448ac52ffe45d194c ≤ v < 3d595affbe00a2e8bf43b9f2947a8efcdc1c059e | CVEProject cvelistV5 (CNA) |
| Linux | Linux | a319185be9f5ad13c2a296d448ac52ffe45d194c ≤ v < ee5afb74688aa6f1f16d8c7e7b6bfaf803fb62fc | CVEProject cvelistV5 (CNA) |
| Linux | Linux | a319185be9f5ad13c2a296d448ac52ffe45d194c ≤ v < fd2bd9fa7700ddf28296486b2598cff2f80cc819 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | a319185be9f5ad13c2a296d448ac52ffe45d194c ≤ v < 8817005efbdfdf5d4e4814cb5dc52b53d12917d7 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | a319185be9f5ad13c2a296d448ac52ffe45d194c ≤ v < 6a01413a4e8fcb0263d7bef5075c5f8f4eb3a8b6 | CVEProject cvelistV5 (CNA) |
References and advisories
6- https://git.kernel.org/stable/c/ee5afb74688aa6f1f16d8c7e7b6bfaf803fb62fc
- https://git.kernel.org/stable/c/b28b862b07257219755d0b0a7fbe5d23b7c9ea91
- https://git.kernel.org/stable/c/3d595affbe00a2e8bf43b9f2947a8efcdc1c059e
- https://git.kernel.org/stable/c/6a01413a4e8fcb0263d7bef5075c5f8f4eb3a8b6
- https://git.kernel.org/stable/c/fd2bd9fa7700ddf28296486b2598cff2f80cc819
- https://git.kernel.org/stable/c/8817005efbdfdf5d4e4814cb5dc52b53d12917d7
Details
- Published
- 2026-07-19
- Last updated
- 2026-10-30
- State
- Published
- Assigner (CNA)
- Linux
Exploit prediction (EPSS)
SSVC assessment (CISA)
- Automatable
- No
- Exploitation
- None
- Technical impact
- Total
Weaknesses (CWE)
- CWE-125Out-of-bounds Read