CVE-2026-93125

/// Technical description

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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References