CVE-2026-72435 (GCVE-0-2026-72435)
Vulnerability from cvelistv5
Published
2026-08-15 05:56
Modified
2026-08-17 05:44
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer() Sashiko pointed out that kfree_rcu() was called before rcu_assign_pointer() in handling the comment extension. Fix the order so that rcu_assign_pointer() called first.
Impacted products
Vendor Product Version
Linux Linux Version: b57b2d1fa53fe8563bdfc66a33b844463b9af285
Version: b57b2d1fa53fe8563bdfc66a33b844463b9af285
Version: b57b2d1fa53fe8563bdfc66a33b844463b9af285
Version: b57b2d1fa53fe8563bdfc66a33b844463b9af285
Version: b57b2d1fa53fe8563bdfc66a33b844463b9af285
Version: b57b2d1fa53fe8563bdfc66a33b844463b9af285
Version: b57b2d1fa53fe8563bdfc66a33b844463b9af285
Version: b57b2d1fa53fe8563bdfc66a33b844463b9af285
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/ipset/ip_set_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c9787d7c24ffd83019f379455e1b97fb4f0f75eb",
              "status": "affected",
              "version": "b57b2d1fa53fe8563bdfc66a33b844463b9af285",
              "versionType": "git"
            },
            {
              "lessThan": "6e98407cb94e035bba98956adc9096a76d8b2a9f",
              "status": "affected",
              "version": "b57b2d1fa53fe8563bdfc66a33b844463b9af285",
              "versionType": "git"
            },
            {
              "lessThan": "50b70f56f3baaff46599f59b2d93fa2540120776",
              "status": "affected",
              "version": "b57b2d1fa53fe8563bdfc66a33b844463b9af285",
              "versionType": "git"
            },
            {
              "lessThan": "d01b4b471f0fc5c396af62845e972ccf99cee29a",
              "status": "affected",
              "version": "b57b2d1fa53fe8563bdfc66a33b844463b9af285",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
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              "version": "b57b2d1fa53fe8563bdfc66a33b844463b9af285",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "b57b2d1fa53fe8563bdfc66a33b844463b9af285",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/ipset/ip_set_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.2"
            },
            {
              "lessThan": "4.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "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": "5.10.261",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.212",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer()\n\nSashiko pointed out that kfree_rcu() was called before\nrcu_assign_pointer() in handling the comment extension.\nFix the order so that rcu_assign_pointer() called first."
        }
      ],
      "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 - The bug is reached only through nfnetlink IPSET commands (ADD/DEL/LIST/SAVE) on NETLINK_GENERIC; nfnetlink_rcv() requires CAP_NET_ADMIN and no remote packet path feeds comment free/replace, so kernel CNA guidance treats netfilter/ipset netlink as Local.\nAC:L - LIST/SAVE dump runs asynchronously without holding the nfnl mutex while mtype_list holds rcu_read_lock and calls ip_set_put_comment; an attacker with CAP_NET_ADMIN can concurrently issue ADD/--exist comment replacement, DEL/flush, or timeout GC to hit the kfree_rcu-before-NULL ordering reliably.\nPR:L - nfnetlink_rcv() gates every ipset command on netlink_net_capable(skb, CAP_NET_ADMIN), which resolves to ns_capable(sock_net()-\u003euser_ns, CAP_NET_ADMIN); unprivileged users obtain this inside a user/network namespace via unshare -Urn and fully control per-netns ipset configuration.\nUI:N - Exploitation is fully attacker-driven through netlink: create a comment-enabled set, start LIST/SAVE dump, and concurrently add/delete/flush elements or let timeout GC run; no victim click, mount, or other deliberate action is required beyond ordinary local control.\nS:U - The RCU use-after-free corrupts kernel heap memory and can yield host privilege escalation or crash, but impact stays within the same kernel security authority and does not cross VM/host, container/host, or IOMMU boundaries.\nC:H - Calling kfree_rcu() before rcu_assign_pointer(NULL) lets dump readers under rcu_read_lock still rcu_dereference(comment-\u003ec) and nla_put_string() reads freed ip_set_comment_rcu kmalloc memory\u2014a classic UAF read usable for arbitrary kernel disclosure with heap grooming.\nI:H - Concurrent free and replacement of RCU-managed comment objects lets an attacker reclaim and control freed slab memory, providing standard paths to arbitrary kernel writes, metadata corruption, and control-flow hijack rather than a bounded or crash-only integrity effect.\nA:H - Stale comment pointer dereference during dump or subsequent slab reuse can immediately kernel-oops or panic the host, and the underlying UAF heap corruption can crash or hang the system even when full exploitation is not attempted."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:44:10.925Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c9787d7c24ffd83019f379455e1b97fb4f0f75eb"
        },
        {
          "url": "https://git.kernel.org/stable/c/6e98407cb94e035bba98956adc9096a76d8b2a9f"
        },
        {
          "url": "https://git.kernel.org/stable/c/50b70f56f3baaff46599f59b2d93fa2540120776"
        },
        {
          "url": "https://git.kernel.org/stable/c/d01b4b471f0fc5c396af62845e972ccf99cee29a"
        },
        {
          "url": "https://git.kernel.org/stable/c/fcb565966534909377a16be5f7b065db2e25c8b5"
        },
        {
          "url": "https://git.kernel.org/stable/c/8087bb360a936a6314d22b567e4b861656943eb6"
        },
        {
          "url": "https://git.kernel.org/stable/c/93a775fd67f3ef34949a9523bfa69403ee74efdd"
        },
        {
          "url": "https://git.kernel.org/stable/c/3ca9982a8882470aa0ac4e8bb9a552b181d1efcd"
        }
      ],
      "title": "netfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72435",
    "datePublished": "2026-08-15T05:56:49.402Z",
    "dateReserved": "2026-08-09T03:40:39.929Z",
    "dateUpdated": "2026-08-17T05:44:10.925Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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