{"id":"CVE-2026-93125","summary":"bpf: Reject rdonly/rdwr_buf_size kfunc arguments that exceed u32 max","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject rdonly/rdwr_buf_size kfunc arguments that exceed u32 max\n\ncheck_kfunc_args() detects a kfunc argument named rdonly_buf_size or\nrdwr_buf_size and stores reg-\u003evar_off.value into meta-\u003er0_size, a u64,\nand does not bound it. check_kfunc_call() later copies that value into\nthe returned register's mem_size field:\n\n  meta-\u003er0_size = reg-\u003evar_off.value;\n  ...\n  regs[BPF_REG_0].mem_size = meta.r0_size;\n\nregs[BPF_REG_0].mem_size is u32. A constant whose upper 32 bits are set\ngets truncated instead of causing a load-time rejection, so the verifier\nrecords a PTR_TO_MEM register with an approximately 4 GiB mem_size for\nwhatever allocation the kfunc returned. A later access check against\nthat register uses the truncated, wrong bound.\n\nReject rdonly_buf_size/rdwr_buf_size values that exceed U32_MAX at the\npoint meta-\u003er0_size is set.","modified":"2026-09-18T03:48:44.249330641Z","published":"2026-09-17T16:11:29.895Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93125.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2aaf67f0516fde29620d0edfc29c01b9ea7ad430"},{"type":"WEB","url":"https://git.kernel.org/stable/c/56a3846830ac95a472297d0cbba75cbff29540bb"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93125.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93125"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae"},{"fixed":"56a3846830ac95a472297d0cbba75cbff29540bb"},{"fixed":"2aaf67f0516fde29620d0edfc29c01b9ea7ad430"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93125.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.1.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93125.json"}}],"schema_version":"1.9.0"}