bpf: Reject rdonly/rdwr_buf_size kfunc arguments that exceed u32 max
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject rdonly/rdwr_buf_size kfunc arguments that exceed u32 max check_kfunc_args() detects a kfunc argument named rdonly_buf_size or rdwr_buf_size and stores reg->var_off.value into meta->r0_size, a u64, and does not bound it. check_kfunc_call() later copies that value into the returned register's mem_size field: meta->r0_size = reg->var_off.value; ... regs[BPF_REG_0].mem_size = meta.r0_size; regs[BPF_REG_0].mem_size is u32. A constant whose upper 32 bits are set gets truncated instead of causing a load-time rejection, so the verifier records a PTR_TO_MEM register with an approximately 4 GiB mem_size for whatever allocation the kfunc returned. A later access check against that register uses the truncated, wrong bound. Reject rdonly_buf_size/rdwr_buf_size values that exceed U32_MAX at the point meta->r0_size is set.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.114, 6.18.57, 7.2.6, 7.3
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
Not affected: 5 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-93125
- 2026-10-03 Alias added: GHSA-vqq3-2x9h-9pmg
- 2026-10-05 CVSS score changed · Red Hat
- 2026-10-09 Affected versions changed · Red Hat
- 2026-10-16 Fix available: Linux/[email protected], Linux/Linux@93a20b14f8627b2d3486e3ec1d3f2e7275a506ec · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@2147065d3a4e1d5d42ae553fef165f17ec5e0e79, Linux/[email protected], Linux/[email protected] +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-29 Affected versions changed · Red Hat
- 2026-10-30 Fix available: Linux/Linux@00bb52be60da16cd5ead4eb9f8ddc9a66d003ff2, Linux/[email protected] · CNA
- 2026-10-30 1 new reference · CNA
- 2026-10-30 Affected versions changed · Red Hat
References
Other 6
- https://git.kernel.org/stable/c/00bb52be60da16cd5ead4eb9f8ddc9a66d003ff2
- https://git.kernel.org/stable/c/2147065d3a4e1d5d42ae553fef165f17ec5e0e79
- https://git.kernel.org/stable/c/b6ac0b5732047d43172b9dfbe6b57b9b8de303c2
- https://git.kernel.org/stable/c/93a20b14f8627b2d3486e3ec1d3f2e7275a506ec
- https://git.kernel.org/stable/c/56a3846830ac95a472297d0cbba75cbff29540bb
- https://git.kernel.org/stable/c/2aaf67f0516fde29620d0edfc29c01b9ea7ad430
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Sources
- CVE-2026-93125 · CVE Program
- CVE-2026-93125 · NVD
- FIRST EPSS
- GHSA-vqq3-2x9h-9pmg · GitHub Advisory Database · CC BY 4.0
- CVE-2026-93125 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences