CVE-2026-97566 (GCVE-0-2026-97566)
Vulnerability from cvelistv5
Published
2026-09-25 10:21
Modified
2026-10-21 12:53
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: mptcp: pm: kernel: drop pending ADD_ADDR when removing ID0 The in-kernel MPTCP path manager can leave a stale ADD_ADDR announcement entry alive when removing the id 0 endpoint. This happens because the id 0 removal path does not tear down pending announcements, unlike the non-zero id path. When the PM later reselects id 0 after adding another signal endpoint, it finds the stale anno_list entry and hits WARN_ON_ONCE(mptcp_pm_is_kernel()) in mptcp_pm_announced_alloc(). Root cause: asymmetry between removal paths. - Non-zero id path: mptcp_nl_remove_subflow_and_signal_addr() calls mptcp_pm_remove_announced() to clean up. - Id 0 path: mptcp_nl_remove_id_zero_address() skips cleanup entirely. Fix by making the id 0 path symmetric: call mptcp_pm_announced_remove() and decrement add_addr_signaled before queuing the RM_ADDR. Subtle detail: signal endpoints are stored in anno_list with port 0, but msk_local carries the connection's local port. In other words, entries linked to ID0 paths should have port == 0. A follow-up patch will ensure that. mptcp_pm_announced_remove() uses use_port=true for comparison. So clear the port before the lookup.
References
Impacted products
Vendor Product Version
Linux Linux Version: 740d798e8767d8a449902b1a1bbc70facfce19b5
Version: 740d798e8767d8a449902b1a1bbc70facfce19b5
Version: 740d798e8767d8a449902b1a1bbc70facfce19b5
Version: 740d798e8767d8a449902b1a1bbc70facfce19b5
Version: 740d798e8767d8a449902b1a1bbc70facfce19b5
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{
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          "programFiles": [
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      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: pm: kernel: drop pending ADD_ADDR when removing ID0\n\nThe in-kernel MPTCP path manager can leave a stale ADD_ADDR announcement\nentry alive when removing the id 0 endpoint. This happens because the id 0\nremoval path does not tear down pending announcements, unlike the non-zero\nid path.\n\nWhen the PM later reselects id 0 after adding another signal endpoint, it\nfinds the stale anno_list entry and hits WARN_ON_ONCE(mptcp_pm_is_kernel())\nin mptcp_pm_announced_alloc().\n\nRoot cause: asymmetry between removal paths.\n- Non-zero id path: mptcp_nl_remove_subflow_and_signal_addr() calls\n  mptcp_pm_remove_announced() to clean up.\n- Id 0 path: mptcp_nl_remove_id_zero_address() skips cleanup entirely.\n\nFix by making the id 0 path symmetric: call mptcp_pm_announced_remove()\nand decrement add_addr_signaled before queuing the RM_ADDR.\n\nSubtle detail: signal endpoints are stored in anno_list with port 0, but\nmsk_local carries the connection\u0027s local port. In other words, entries\nlinked to ID0 paths should have port == 0. A follow-up patch will ensure\nthat. mptcp_pm_announced_remove() uses use_port=true for comparison. So\nclear the port before the lookup."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:53:19.223Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/189d60057e5f3d6a62e3d71a3cc428c9150bc14f"
        },
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          "url": "https://git.kernel.org/stable/c/bacf23e7c9876c9f4170166b3597cb22ea3ed39b"
        },
        {
          "url": "https://git.kernel.org/stable/c/d4a67a880654e1bfe318a31bea0bdbb026a09ade"
        },
        {
          "url": "https://git.kernel.org/stable/c/545616b4e7325be3c61fc082538cb06d14f7b1db"
        },
        {
          "url": "https://git.kernel.org/stable/c/2ac7d6e620764f1fc79eb4edd3610a7a661981ca"
        }
      ],
      "title": "mptcp: pm: kernel: drop pending ADD_ADDR when removing ID0",
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  },
  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97566",
    "datePublished": "2026-09-25T10:21:53.068Z",
    "dateReserved": "2026-09-24T16:01:01.155Z",
    "dateUpdated": "2026-10-21T12:53:19.223Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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