CVE-2026-64123 (GCVE-0-2026-64123)
Vulnerability from cvelistv5
Published
2026-07-19 15:40
Modified
2026-08-05 12:39
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net: hsr: defer node table free until after RCU readers HSR node-list and node-status generic-netlink operations run under rcu_read_lock(). They walk hsr->node_db through hsr_get_next_node() and hsr_get_node_data(), but RTM_DELLINK teardown removes the same node table with plain list_del() and frees each node immediately. That lets a generic-netlink reader hold a struct hsr_node pointer across hsr_dellink(). In a KASAN build, widening the reader window after hsr_get_next_node() obtains the node reproduces a slab-use-after-free when the reader copies node->macaddress_A; the freeing stack is hsr_del_nodes() from hsr_dellink(). Use list_del_rcu() and defer the free through the existing hsr_free_node_rcu() callback. This matches the lifetime rule used by the HSR prune paths, which already delete nodes with list_del_rcu() and call_rcu().
References
Impacted products
Vendor Product Version
Linux Linux Version: b9a1e627405d68d475a3c1f35e685ccfb5bbe668
Version: b9a1e627405d68d475a3c1f35e685ccfb5bbe668
Version: b9a1e627405d68d475a3c1f35e685ccfb5bbe668
Version: b9a1e627405d68d475a3c1f35e685ccfb5bbe668
Version: b9a1e627405d68d475a3c1f35e685ccfb5bbe668
Version: b9a1e627405d68d475a3c1f35e685ccfb5bbe668
Version: b9a1e627405d68d475a3c1f35e685ccfb5bbe668
Version: 08523d5a2f4a9e4202e00d282c164d453cabe2d2
Version: 5.2.12   ≤
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/hsr/hsr_framereg.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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              "version": "5.2.12",
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        {
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          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "5.3"
            },
            {
              "lessThan": "5.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.210",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.93",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.259",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.210",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.176",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.143",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.93",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.2.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: hsr: defer node table free until after RCU readers\n\nHSR node-list and node-status generic-netlink operations run under\nrcu_read_lock(). They walk hsr-\u003enode_db through hsr_get_next_node() and\nhsr_get_node_data(), but RTM_DELLINK teardown removes the same node table\nwith plain list_del() and frees each node immediately.\n\nThat lets a generic-netlink reader hold a struct hsr_node pointer across\nhsr_dellink(). In a KASAN build, widening the reader window after\nhsr_get_next_node() obtains the node reproduces a slab-use-after-free\nwhen the reader copies node-\u003emacaddress_A; the freeing stack is\nhsr_del_nodes() from hsr_dellink().\n\nUse list_del_rcu() and defer the free through the existing\nhsr_free_node_rcu() callback. This matches the lifetime rule used by the\nHSR prune paths, which already delete nodes with list_del_rcu() and\ncall_rcu()."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires local netlink access: generic-netlink HSR_C_GET_NODE_LIST/HSR_C_GET_NODE_STATUS and rtnetlink RTM_DELLINK. The bug is not reachable via HSR/PRP network frames despite HSR being a network redundancy protocol.\nAC:L - The attacker controls both sides of the race by issuing concurrent GENL node queries and RTM_DELLINK on separate threads; no unpredictable victim state or memory layout is required beyond having an HSR interface configured.\nPR:L - Reliable exploitation requires CAP_NET_ADMIN to delete the HSR device via RTM_DELLINK (and typically to create it); CAP_NET_ADMIN is obtainable by an unprivileged user through user namespaces (unshare -Urn), and the GENL read operations themselves carry no admin-perm flag.\nUI:N - No victim interaction is required; the race is triggered entirely by the attacker\u0027s own concurrent netlink operations.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same kernel/host security boundary, not a cross-boundary escape such as VM or sandbox breakout.\nC:H - This is a slab use-after-free on struct hsr_node; freed objects can be reallocated and read through fields like macaddress_A/B and block_buf, enabling arbitrary kernel memory disclosure.\nI:H - UAF on a kmalloc\u0027d hsr_node with spinlock and pointer fields (block_buf, seq_blocks) provides standard heap-spray primitives for arbitrary kernel writes and potential code execution.\nA:H - Use-after-free on hsr_node during RCU-protected traversal causes kernel oops/panic even without full exploitation, as confirmed by KASAN on the macaddress_A copy path."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:39:29.748Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0ea70fb46940620848c08d9d399455c9e82fecdb"
        },
        {
          "url": "https://git.kernel.org/stable/c/8be6685cdd1255bcc85f9b59e4bfc313aefc5c1b"
        },
        {
          "url": "https://git.kernel.org/stable/c/c5580114e0492bcd2e0a37613ed4c311e3fa3d4d"
        },
        {
          "url": "https://git.kernel.org/stable/c/7713f4aafb577ff49fa67f0488d9c7dddc64d6ce"
        },
        {
          "url": "https://git.kernel.org/stable/c/6324423a8e6591f41a16c09a8f9a84e554ac147c"
        },
        {
          "url": "https://git.kernel.org/stable/c/8c3af18bb0d7c921a5219194037509463eb2ffde"
        },
        {
          "url": "https://git.kernel.org/stable/c/aaec7096f9961eb223b5b149abe9495525c205d9"
        }
      ],
      "title": "net: hsr: defer node table free until after RCU readers",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64123",
    "datePublished": "2026-07-19T15:40:21.161Z",
    "dateReserved": "2026-07-19T07:54:57.036Z",
    "dateUpdated": "2026-08-05T12:39:29.748Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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