{"id":"CVE-2026-74314","summary":"bpf: Cancel special fields on map value recycle","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Cancel special fields on map value recycle\n\nMap update and delete paths currently call bpf_obj_free_fields() when a\nvalue is being replaced or recycled. That makes field destruction depend\non the context of the update/delete operation. For tracing programs this\ncan include NMI context, where referenced kptr destructors, uptr\nunpinning, and graph root destruction are not generally safe.\n\nIntroduce bpf_obj_cancel_fields() for the reusable-value path. It only\nperforms NMI-safe cleanup for timer, workqueue, and task_work fields.\nFields that need full destruction are left attached to the recycled value\nand are destroyed by the final cleanup path instead.\n\nSwitch array and hashtab update/delete/recycle paths to this cancel\nhelper. Keep bpf_obj_free_fields() for final map destruction and for\nbpf_mem_alloc destructors. Preallocated hashtabs do not have allocator\ndestructors, so teardown continues to walk the normal and extra elements\nand fully destroy their fields.\n\nThis deliberately relaxes the eager-free semantics of map update/delete\nfor special fields. Programs that relied on a recycled map slot becoming\nempty immediately after update/delete were relying on behavior that\ncannot be implemented safely from every BPF execution context without\noffloading arbitrary destructors.\n\nThere is a chance this change breaks programs making assumptions\nregarding the eager freeing of fields. If so, we can relax semantics to\ncancellation only when irqs_disabled() is true in the future. However,\ntheoretically, map values that get reused eagerly already have weaker\nguarantees as parallel users can recreate freed fields before the new\nelement becomes visible again.","modified":"2026-08-18T03:56:46.367950611Z","published":"2026-08-15T05:58:12.766Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74314.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/9ea734e2cc0143d7429ab7dc0b20c85e5836183c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a3a81d247651218e47153f2d2afd7aee236726fd"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74314.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74314"},{"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":"14a324f6a67ef6a53e04362a70160a47eb8afffa"},{"fixed":"9ea734e2cc0143d7429ab7dc0b20c85e5836183c"},{"fixed":"a3a81d247651218e47153f2d2afd7aee236726fd"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"f0462d38589422bc9e27fd3c6343dfeb6b3db2f9"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.18.18"},{"fixed":"5.19"}]}],"versions":["v5.18.17","v5.18.16","v5.18.15","v5.18","v5.18.14","v5.18.13","v5.18.12","v5.18.11","v5.18.10","v5.18.9","v5.18.8","v5.18-rc1","v5.18.7","v5.18.6","v5.18.5","v5.18.4","v5.18.3","v5.18.2","v5.18.1","v5.18-rc7","v5.18-rc2","v5.18-rc5","v5.17","v5.18-rc4","v5.18-rc3","v5.18-rc6","v5.17-rc6","v5.17-rc4","v5.17-rc8","v5.17-rc7","v5.17-rc1","v5.17-rc3","v5.17-rc2","v5.17-rc5","v5.16","v5.16-rc1","v5.16-rc8","v5.16-rc5","v5.16-rc6","v5.16-rc7","v5.16-rc3","v5.16-rc2","v5.16-rc4","v5.15","v5.15-rc2","v5.15-rc1","v5.15-rc4","v5.15-rc7","v5.15-rc3","v5.15-rc5","v5.15-rc6","v5.14","v5.14-rc3","v5.14-rc1","v5.14-rc2","v5.14-rc7","v5.14-rc6","v5.13-rc1","v5.14-rc5","v5.14-rc4","v5.13","v5.13-rc6","v5.13-rc7","v5.13-rc3","v5.13-rc2","v5.13-rc4","v5.13-rc5","v5.12","v5.12-rc2","v5.12-rc1-dontuse","v5.12-rc1","v5.12-rc8","v5.12-rc3","v5.12-rc7","v5.12-rc5","v5.12-rc6","v5.12-rc4","v5.10","v5.11","v5.11-rc3","v5.11-rc7","v5.11-rc6","v5.11-rc5","v5.11-rc1","v5.11-rc4","v5.11-rc2","v5.10-rc1","v5.10-rc7","v5.10-rc4","v5.10-rc3","v5.10-rc6","v5.9","v5.10-rc2","v5.10-rc5","v5.9-rc1","v5.9-rc7","v5.9-rc8","v5.9-rc6","v5.9-rc4","v5.9-rc5","v5.9-rc3","v5.9-rc2","v5.8","v5.7","v5.8-rc2","v5.8-rc1","v5.8-rc7","v5.8-rc5","v5.8-rc3","v5.8-rc4","v5.8-rc6","v5.7-rc4","v5.7-rc7","v5.7-rc1","v5.7-rc3","v5.7-rc2","v5.7-rc5","v5.7-rc6","v5.6","v5.6-rc1","v5.6-rc7","v5.6-rc6","v5.6-rc3","v5.6-rc4","v5.6-rc2","v5.6-rc5","v5.5","v5.5-rc5","v5.5-rc7","v5.5-rc2","v5.5-rc1","v5.4","v5.5-rc4","v5.5-rc3","v5.5-rc6","v5.4-rc1","v5.4-rc6","v5.4-rc3","v5.4-rc4","v5.4-rc8","v5.4-rc7","v5.4-rc5","v5.3","v5.4-rc2","v5.3-rc5","v5.3-rc1","v5.3-rc2","v5.3-rc3","v5.3-rc8","v5.3-rc7","v5.3-rc4","v5.2","v5.3-rc6","v5.2-rc2","v5.2-rc7","v5.2-rc4","v5.2-rc1","v5.2-rc5","v5.2-rc6","v5.2-rc3","v5.1","v5.0-rc8","v5.1-rc7","v5.1-rc1","v5.1-rc6","v5.1-rc5","v5.0","v5.1-rc3","v5.1-rc2","v5.1-rc4","v5.0-rc1","v5.0-rc4","v5.0-rc3","v5.0-rc6","v5.0-rc7","v5.0-rc2","v5.0-rc5","v4.20-rc1","v4.19","v4.20","v4.20-rc7","v4.20-rc5","v4.20-rc6","v4.20-rc4","v4.20-rc2","v4.20-rc3","v4.19-rc2","v4.19-rc8","v4.19-rc4","v4.19-rc1","v4.19-rc7","v4.19-rc6","v4.19-rc5","v4.19-rc3","v4.18","v4.18-rc1","v4.18-rc8","v4.18-rc2","v4.18-rc5","v4.18-rc6","v4.18-rc7","v4.17","v4.18-rc3","v4.18-rc4","v4.17-rc1","v4.17-rc2","v4.17-rc7","v4.17-rc3","v4.17-rc4","v4.16","v4.17-rc6","v4.17-rc5","v4.16-rc7","v4.16-rc4","v4.16-rc1","v4.16-rc2","v4.16-rc5","v4.16-rc3","v4.16-rc6","v4.14","v4.15","v4.15-rc1","v4.15-rc4","v4.15-rc9","v4.15-rc8","v4.15-rc7","v4.15-rc3","v4.15-rc2","v4.15-rc5","v4.15-rc6","v4.14-rc1","v4.14-rc7","v4.14-rc3","v4.13","v4.14-rc8","v4.14-rc4","v4.14-rc6","v4.14-rc2","v4.14-rc5","v4.13-rc2","v4.13-rc1","v4.13-rc3","v4.13-rc7","v4.13-rc4","v4.13-rc5","v4.13-rc6","v4.12-rc1","v4.12","v4.12-rc5","v4.12-rc7","v4.12-rc6","v4.12-rc4","v4.12-rc2","v4.12-rc3","v4.11","v4.11-rc1","v4.11-rc6","v4.11-rc8","v4.11-rc7","v4.11-rc3","v4.11-rc5","v4.11-rc2","v4.11-rc4","v4.10","v4.9","v4.10-rc8","v4.10-rc3","v4.10-rc1","v4.10-rc7","v4.10-rc6","v4.10-rc2","v4.10-rc5","v4.10-rc4","v4.9-rc7","v4.9-rc6","v4.9-rc8","v4.9-rc1","v4.9-rc5","v4.9-rc3","v4.9-rc4","v4.9-rc2","v4.8","v4.8-rc8","v4.8-rc2","v4.8-rc1","v4.8-rc7","v4.8-rc6","v4.8-rc5","v4.8-rc4","v4.8-rc3","v4.7","v4.7-rc4","v4.7-rc2","v4.7-rc1","v4.7-rc7","v4.7-rc6","v4.7-rc3","v4.7-rc5","v4.6","v4.6-rc1","v4.6-rc6","v4.6-rc4","v4.6-rc7","v4.6-rc5","v4.5-rc4","v4.6-rc2","v4.6-rc3","v4.5","v4.4","v4.5-rc1","v4.5-rc6","v4.5-rc2","v4.5-rc7","v4.5-rc5","v4.5-rc3","v4.4-rc1","v4.4-rc2","v4.4-rc8","v4.4-rc3","v4.4-rc7","v4.4-rc5","v4.4-rc6","v4.4-rc4","v4.3","v4.3-rc1","v4.3-rc6","v4.3-rc4","v4.3-rc2","v4.3-rc7","v4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