GHSA-G5F7-QJ4Q-4W5V

Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-10 15:33
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: defer link RX stats percpu free to RCU

sta_remove_link() frees a removed MLO link's RX stats percpu buffer right away, but defers only the link container to RCU:

sta_info_free_link(&alloc->info);
kfree_rcu(alloc, rcu_head);

The RX fast path reads link_sta under rcu_read_lock and writes the percpu stats. A reader that resolved link_sta before the removal keeps the pointer. The container stays alive from the kfree_rcu, so the read still works. But the percpu block it points to is already freed. This needs uses_rss. That is when pcpu_rx_stats exists.

The full STA teardown frees the deflink stats only after synchronize_net(). The link removal path had no such barrier. The race is hard to win in practice, but the free should still wait for RCU.

Free the link together with its data from a single RCU callback, so the percpu block is reclaimed only after readers drain.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-68409"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:20:34Z",
    "severity": null
  },
  "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\u0027s RX stats percpu buffer right\naway, but defers only the link container to RCU:\n\n\tsta_info_free_link(\u0026alloc-\u003einfo);\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.",
  "id": "GHSA-g5f7-qj4q-4w5v",
  "modified": "2026-08-10T15:33:50Z",
  "published": "2026-08-10T15:33:50Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68409"
    },
    {
      "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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