{"id":"CVE-2026-98033","summary":"bpf: Preserve inner map identity in callback frames","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Preserve inner map identity in callback frames\n\nCallback frame constructors initialize map-typed argument registers with\n__mark_reg_known_zero() and then restore map_ptr. This clears map_uid,\nwhich is the only field distinguishing inner maps that share an\ninner_map_meta template.\n\nWhen a timer callback invokes bpf_for_each_map_elem() on a second inner\nmap, both the saved first map and the second map value can reach the nested\ncallback as the same template with map_uid zero. bpf_timer_init() then\naccepts pairing the timer from the second map with the first map.\n\nThe runtime records the first map in the timer without taking a reference.\nFreeing that map does not find the timer stored in the second map, so a\nlater timer callback dereferences the freed map.\n\nCopy map_uid from the same caller register as map_ptr when constructing\nfor-each, timer/workqueue, and task-work callback arguments. The existing\nidentity check can then reject mismatched inner maps while allowing a\ncallback value to be paired with its actual map.","modified":"2026-09-26T03:48:31.631370248Z","published":"2026-09-25T10:23:48.761Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98033.json","cna_assigner":"Linux"},"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/66ff2eff093d2a0838f39c713eeb590bc0946c2a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b90c5d770dad910fb89e6c1b15052a8a1e8db752"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98033.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98033"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"69c087ba6225b574afb6e505b72cb75242a3d844"},{"fixed":"66ff2eff093d2a0838f39c713eeb590bc0946c2a"},{"fixed":"b90c5d770dad910fb89e6c1b15052a8a1e8db752"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98033.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.13.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98033.json"}}],"schema_version":"1.9.0"}