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CVE-2026-93125

bpf: Reject rdonly/rdwr_buf_size kfunc arguments that exceed u32 max PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae before 2147065d3a4e1d5d42ae553fef165f17ec5e0e79; affected eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae before b6ac0b5732047d43172b9dfbe6b57b9b8de303c2; affected eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae before 93a20b14f8627b2d3486e3ec1d3f2e7275a506ec; affected eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae before 56a3846830ac95a472297d0cbba75cbff29540bb; affected eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae before 2aaf67f0516fde29620d0edfc29c01b9ea7ad430
Linux / Linuxaffected 6.1; unaffected 0 before 6.1; unaffected 6.6.160 through 6.6.*; unaffected 6.12.114 through 6.12.*; unaffected 6.18.57 through 6.18.*; unaffected 7.2.6 through 7.2.*; unaffected 7.3 through *

CWE

No CWE identifiers supplied.

References