{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68409", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.390Z", "datePublished": "2026-08-10T12:04:29.238Z", "dateUpdated": "2026-08-17T05:04:59.807Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:04:59.807Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:A - The race is driven entirely over the air: the RX fast path writing the freed percpu stats is fed by received 802.11 data frames, and the link removal that frees them is triggered by AP-originated ML reconfiguration/association-response handling in ieee80211_ml_reconf_work(). A rogue AP or frame injector within radio range of the victim station suffices, so this is adjacent (Wi-Fi) rather than routable network access.\nAC:L - The attacker controls both sides of the race — it supplies the RX traffic stream that dereferences link_sta and writes pcpu_rx_stats, and it triggers the MLO link removal that frees that percpu block — and can repeat link add/remove cycles indefinitely under high packet rates spread across many CPUs by RSS. No condition outside the attacker's influence is needed beyond a mainstream RSS-capable MLO driver (iwlwifi, ath11k/ath12k).\nPR:N - No privileges or accounts on the victim system are required; the frames come from the peer AP, and a rogue AP or spoofed ML reconfiguration/data frames reach the code with no authorization on the target host.\nUI:N - Frame reception, MLO link reconfiguration and station link teardown are all handled automatically by mac80211 with no action by the device's user.\nS:U - The use-after-free corrupts kernel memory within the same kernel security authority; no VM, IOMMU or sandbox boundary is crossed.\nC:H - The freed percpu block can be reallocated to other subsystems, and the RX path continues reading fields such as last_signal, chains and counters from it, so attacker-influenced reuse of that memory can expose kernel data; per use-after-free scoring this is treated as high confidentiality impact.\nI:H - The RX fast path performs repeated writes (last_rx, last_rate, fragments, packets, chain_signal_last) into the already-freed percpu allocation, corrupting whatever percpu data is reallocated there — an attacker-timed write primitive into arbitrary recycled kernel state.\nA:H - Writing through a freed percpu pointer from the RX hot path corrupts kernel allocator state and unrelated percpu data, readily producing oopses or panics; KASAN-instrumented kernels report the use-after-free outright." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/mac80211/sta_info.c" ], "versions": [ { "version": "c71420db653aba30a234d1e4cf86dde376e604fa", "lessThan": "2aa1789880fa5e41049b0f6a74a4fc2fa1997610", "status": "affected", "versionType": "git" }, { "version": "c71420db653aba30a234d1e4cf86dde376e604fa", "lessThan": "a03fceae0c65b31ce31840dac5e26684ceecb65b", "status": "affected", "versionType": "git" }, { "version": "c71420db653aba30a234d1e4cf86dde376e604fa", "lessThan": "aa2eb62525188269cdd402a583b9a8ed94657ff0", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/mac80211/sta_info.c" ], "versions": [ { "version": "6.0", "status": "affected" }, { "version": "0", "lessThan": "6.0", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2aa1789880fa5e41049b0f6a74a4fc2fa1997610" }, { "url": "https://git.kernel.org/stable/c/a03fceae0c65b31ce31840dac5e26684ceecb65b" }, { "url": "https://git.kernel.org/stable/c/aa2eb62525188269cdd402a583b9a8ed94657ff0" } ], "title": "wifi: mac80211: defer link RX stats percpu free to RCU", "x_generator": { "engine": "bippy-1.2.0" } } } }