Vulnerability-Lookup

FKIE_CVE-2026-68409

Vulnerability from fkie_nvd - Published: 2026-08-10 13:20 - Updated: 2026-08-17 06:17

Severity

8.8 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

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.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2aa1789880fa5e41049b0f6a74a4fc2fa1997610
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a03fceae0c65b31ce31840dac5e26684ceecb65b
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/aa2eb62525188269cdd402a583b9a8ed94657ff0

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mac80211/sta_info.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2aa1789880fa5e41049b0f6a74a4fc2fa1997610",
              "status": "affected",
              "version": "c71420db653aba30a234d1e4cf86dde376e604fa",
              "versionType": "git"
            },
            {
              "lessThan": "a03fceae0c65b31ce31840dac5e26684ceecb65b",
              "status": "affected",
              "version": "c71420db653aba30a234d1e4cf86dde376e604fa",
              "versionType": "git"
            },
            {
              "lessThan": "aa2eb62525188269cdd402a583b9a8ed94657ff0",
              "status": "affected",
              "version": "c71420db653aba30a234d1e4cf86dde376e604fa",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/mac80211/sta_info.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "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\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": "CVE-2026-68409",
  "lastModified": "2026-08-17T06:17:49.857",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-10T13:20:34.537",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2aa1789880fa5e41049b0f6a74a4fc2fa1997610"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a03fceae0c65b31ce31840dac5e26684ceecb65b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/aa2eb62525188269cdd402a583b9a8ed94657ff0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-68409 (GCVE-0-2026-68409)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:04 – Updated: 2026-08-17 05:04

Title

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

Summary

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/2aa1789880fa5e410…
https://git.kernel.org/stable/c/a03fceae0c65b31ce…
https://git.kernel.org/stable/c/aa2eb62525188269c…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c71420db653aba30a234d1e4cf86dde376e604fa , < 2aa1789880fa5e41049b0f6a74a4fc2fa1997610 (git) Affected: c71420db653aba30a234d1e4cf86dde376e604fa , < a03fceae0c65b31ce31840dac5e26684ceecb65b (git) Affected: c71420db653aba30a234d1e4cf86dde376e604fa , < aa2eb62525188269cdd402a583b9a8ed94657ff0 (git)
Linux	Linux	Affected: 6.0 Unaffected: 0 , < 6.0 (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mac80211/sta_info.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2aa1789880fa5e41049b0f6a74a4fc2fa1997610",
              "status": "affected",
              "version": "c71420db653aba30a234d1e4cf86dde376e604fa",
              "versionType": "git"
            },
            {
              "lessThan": "a03fceae0c65b31ce31840dac5e26684ceecb65b",
              "status": "affected",
              "version": "c71420db653aba30a234d1e4cf86dde376e604fa",
              "versionType": "git"
            },
            {
              "lessThan": "aa2eb62525188269cdd402a583b9a8ed94657ff0",
              "status": "affected",
              "version": "c71420db653aba30a234d1e4cf86dde376e604fa",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/mac80211/sta_info.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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\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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "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 \u2014 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 \u2014 and can repeat link add/remove cycles indefinitely under high packet rates spread across many CPUs by RSS. No condition outside the attacker\u0027s 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\u0027s 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 \u2014 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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:04:59.807Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "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"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68409",
    "datePublished": "2026-08-10T12:04:29.238Z",
    "dateReserved": "2026-07-30T09:28:09.390Z",
    "dateUpdated": "2026-08-17T05:04:59.807Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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FKIE_CVE-2026-68409

CVE-2026-68409 (GCVE-0-2026-68409)

Tags

Sightings

Nomenclature