{"id":"CVE-2026-90312","summary":"bpf: Check load-acquire src ptr type before the load","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Check load-acquire src ptr type before the load\n\ncheck_atomic_load() calls check_load_mem() before atomic_ptr_type_ok().\nFor a load-acquire that fetches into its own source register (dst_reg ==\nsrc_reg), check_load_mem() overwrites src_reg's type with the type of the\nloaded value, so the subsequent atomic_ptr_type_ok() no longer sees the\nsource pointer and fails to reject the disallowed types (ctx, pkt,\nflow_keys, sock).\n\nSince bpf_convert_ctx_accesses() does not rewrite atomic loads, the raw\naccess to the underlying kernel object is left in place. The destination\ntype is taken from the ctx access itself, so a load-acquire of the sk\nfield of struct __sk_buff for example leaves the register typed as\nPTR_TO_SOCK_COMMON_OR_NULL, which type_is_sk_pointer() does not match\neither, while it actually holds unconverted struct sk_buff bytes. Once\nthe NULL check has passed this is a type confusion, not just a leak of\nkernel data.\n\nValidate src_reg with check_reg_arg() and check the source pointer type\nwith atomic_ptr_type_ok() before the load again, mirroring\ncheck_atomic_rmw(). Out-of-range register numbers are already rejected\nearlier by check_and_resolve_insns() (commit 503d21ef8eac (\"bpf: Do\nregister range validation early\")), and the only exemption there,\nis_stack_arg_ldx(), requires BPF_LDX | BPF_MEM | BPF_DW and thus never\nmatches a BPF_ATOMIC insn. atomic_ptr_type_ok() can therefore not\ndereference register state out of bounds, that is, the out-of-bounds\nread addressed by the Fixes commit below does not reappear (as proven\nalso via selftest).","modified":"2026-09-19T03:47:25.754504787Z","published":"2026-09-17T16:08:32.287Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90312.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/422a416041172af1ac610736d5f556d22b31b115"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6ee7b00888498cf387dd30729e18a05328b94709"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b87803391baa7e0bef60549d8841f12e549ad057"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90312.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90312"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c03bb2fa327e4c25d6c5360a8803a4b1cdc2d0b9"},{"fixed":"6ee7b00888498cf387dd30729e18a05328b94709"},{"fixed":"422a416041172af1ac610736d5f556d22b31b115"},{"fixed":"b87803391baa7e0bef60549d8841f12e549ad057"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90312.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.15.0"},{"fixed":"6.18.52"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90312.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}