{"id":"CVE-2026-68409","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-68409","summary":"wifi: mac80211: defer link RX stats percpu free to RCU","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mac80211: defer link RX stats percpu free to RCU\n\nsta_remove_link() frees a removed MLO link's RX stats percpu buffer right\naway, but defers only the link container to RCU:\n\n\tsta_info_free_link(&alloc->info);\n\tkfree_rcu(alloc, rcu_head);\n\nThe RX fast path reads link_sta under rcu_read_lock and writes the percpu\nstats. A reader that resolved link_sta before the removal keeps the\npointer. The container stays alive from the kfree_rcu, so the read still\nworks. But the percpu block it points to is already freed. This needs\nuses_rss. That is when pcpu_rx_stats exists.\n\nThe full STA teardown frees the deflink stats only after\nsynchronize_net(). The link removal path had no such barrier. The race is\nhard to win in practice, but the free should still wait for RCU.\n\nFree the link together with its data from a single RCU callback, so the\npercpu block is reclaimed only after readers drain.","published":"2026-08-10T12:04:29.238Z","modified":"2026-08-14T04:03:38.860132836Z","cvss":{"score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.18.42"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2aa1789880fa5e41049b0f6a74a4fc2fa1997610"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a03fceae0c65b31ce31840dac5e26684ceecb65b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/aa2eb62525188269cdd402a583b9a8ed94657ff0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68409.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68409"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-14T04:03:38.860132836Z"}}