{"id":"CVE-2026-43070","summary":"bpf: Reset register ID for BPF_END value tracking","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reset register ID for BPF_END value tracking\n\nWhen a register undergoes a BPF_END (byte swap) operation, its scalar\nvalue is mutated in-place. If this register previously shared a scalar ID\nwith another register (e.g., after an `r1 = r0` assignment), this tie must\nbe broken.\n\nCurrently, the verifier misses resetting `dst_reg-\u003eid` to 0 for BPF_END.\nConsequently, if a conditional jump checks the swapped register, the\nverifier incorrectly propagates the learned bounds to the linked register,\nleading to false confidence in the linked register's value and potentially\nallowing out-of-bounds memory accesses.\n\nFix this by explicitly resetting `dst_reg-\u003eid` to 0 in the BPF_END case\nto break the scalar tie, similar to how BPF_NEG handles it via\n`__mark_reg_known`.","modified":"2026-07-08T08:13:30.277192517Z","published":"2026-05-05T15:23:28.819Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43070.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0d15c3611a2cc5d08993545d4032055ae10ae2c1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a17443af874229408ce6b78e2c8a2b5adeb4b7d8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a3125bc01884431d30d731461634c8295b6f0529"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43070.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43070"},{"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":"4c03342e5ac532fb34d13a7b51dd7261dfc48963"},{"fixed":"a17443af874229408ce6b78e2c8a2b5adeb4b7d8"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d00ce96623a69a100ad79675d0e85fda3c50d89b"},{"fixed":"0d15c3611a2cc5d08993545d4032055ae10ae2c1"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"9d21199842247ab05c675fb9b6c6ca393a5c0024"},{"fixed":"a3125bc01884431d30d731461634c8295b6f0529"}]}],"versions":["v6.18.20","v6.18.19","v6.18.18","v6.18.17","v6.19.10","v6.19.9","v6.19.8","v6.19.7"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43070.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.18.17"},{"fixed":"6.18.21"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.7"},{"fixed":"6.19.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43070.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}