CVE-2026-93288 (GCVE-0-2026-93288)

Vulnerability from cvelistv5 – Published: 2026-09-24 16:02 – Updated: 2026-09-25 12:42
VLAI
Title
netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state sashiko reports: "nfnl_log_net_exit() calls nf_log_unset(), which clears the logger pointer without an RCU grace period. Immediately after, ops_free_list() frees the per-net state while concurrent packets might still be executing nf_log_packet() under rcu_read_lock()." Clear the pointer via .pre_exit to make sure rcu readers have completed before pernet storage is free'd. The change in nf_log_syslog.c is only done for consistency: it doesn't use pernet data.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: c83fa19603bdaeef17b815713dbbe3230c8a34ee , < f4461654374576e9d5d0245fd534c46ad8509051 (git)
Affected: c83fa19603bdaeef17b815713dbbe3230c8a34ee , < dc20050b6b12ca58066715d088e1a537535d938d (git)
Affected: c83fa19603bdaeef17b815713dbbe3230c8a34ee , < 33d1469b0124cc0baaea7a2032123b77a81e0940 (git)
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Linux Linux Affected: 4.12
Unaffected: 0 , < 4.12 (semver)
Unaffected: 6.12.111 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_log_syslog.c",
            "net/netfilter/nfnetlink_log.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "f4461654374576e9d5d0245fd534c46ad8509051",
              "status": "affected",
              "version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
              "versionType": "git"
            },
            {
              "lessThan": "dc20050b6b12ca58066715d088e1a537535d938d",
              "status": "affected",
              "version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
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          "product": "Linux",
          "programFiles": [
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            "net/netfilter/nfnetlink_log.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.12"
            },
            {
              "lessThan": "4.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.18.53",
              "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": "6.12.111",
                  "versionStartIncluding": "4.12",
                  "vulnerable": true
                },
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                  "versionStartIncluding": "4.12",
                  "vulnerable": true
                },
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "4.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state\n\nsashiko reports: \"nfnl_log_net_exit() calls nf_log_unset(), which\nclears the logger pointer without an RCU grace period.  Immediately after,\nops_free_list() frees the per-net state while concurrent packets might\nstill be executing nf_log_packet() under rcu_read_lock().\"\n\nClear the pointer via .pre_exit to make sure rcu readers have completed\nbefore pernet storage is free\u0027d.  The change in nf_log_syslog.c is only\ndone for consistency: it doesn\u0027t use pernet data."
        }
      ],
      "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 UAF is in nfnl_log_net_exit() (unset moved to nfnl_log_net_pre_exit): cleanup_net() frees nfnl_log_net via ops_free_list() while nf_log_packet()\u2192nfulnl_log_packet() still uses nfnl_log_pernet(). Setup is local NETLINK_NETFILTER nfulnl_recv_config (NFULNL_CFG_CMD_PF_BIND); no remote protocol message carries the bug.\nAC:L - The attacker PF_BINDs nfulnl_logger through nfulnl_recv_config, generates packets that enter nf_log_packet() (conntrack nf_l4proto_log_invalid() while those hooks still exist, or NFLOG), and drops the netns so cleanup_net() races nfnl_log_net_exit()/ops_free_list() against that reader; both sides are attacker-controlled.\nPR:L - nfnetlink_rcv() requires CAP_NET_ADMIN via netlink_net_capable() in sock_net(skb-\u003esk)-\u003euser_ns before nfulnl_recv_config can bind the logger; an unprivileged user obtains that capability in a user+net namespace (unshare -Urn).\nUI:N - The attacker issues nfulnl_recv_config, injects the logged packets, and destroys their own netns; no victim mount, file open, or other interaction is required.\nS:U - The slab UAF of struct nfnl_log_net inside nfulnl_log_packet()/instance_lookup_get_rcu() is host-kernel memory corruption in the same kernel authority, not a VM escape or IOMMU/DMA bypass.\nC:H - After ops_free_list() kfree()s the per-net object, nfulnl_log_packet() still calls nfnl_log_pernet() and instance_lookup_get_rcu() walks the freed instance_table hlist, a slab UAF that can be reclaimed for arbitrary kernel reads.\nI:H - Use-after-free of nfnl_log_net\u0027s instance_table and the resulting nfulnl_instance pointer chase (hlist, inst-\u003elock, inst-\u003eskb) is a heap UAF write primitive that can hijack control flow.\nA:H - instance_lookup_get_rcu()/nfulnl_log_packet() dereferencing the freed nfnl_log_net can oops or panic the kernel even when the UAF is not turned into a full exploit."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T12:42:45.191Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f4461654374576e9d5d0245fd534c46ad8509051"
        },
        {
          "url": "https://git.kernel.org/stable/c/dc20050b6b12ca58066715d088e1a537535d938d"
        },
        {
          "url": "https://git.kernel.org/stable/c/33d1469b0124cc0baaea7a2032123b77a81e0940"
        }
      ],
      "title": "netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93288",
    "datePublished": "2026-09-24T16:02:12.144Z",
    "dateReserved": "2026-09-17T16:02:15.099Z",
    "dateUpdated": "2026-09-25T12:42:45.191Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-28",
      "epss": "0.00127",
      "percentile": "0.02021"
    },
    "microsoft_vex": {
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      "cve": "CVE-2026-93288",
      "id": "msrc_CVE-2026-93288",
      "initial_release_date": "2026-09-28T01:51:56.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-93288.json",
      "version": "1"
    },
    "nvd": {
      "cve": {
        "affected": [
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              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/netfilter/nf_log_syslog.c",
                  "net/netfilter/nfnetlink_log.c"
                ],
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                "vendor": "Linux",
                "versions": [
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        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state\n\nsashiko reports: \"nfnl_log_net_exit() calls nf_log_unset(), which\nclears the logger pointer without an RCU grace period.  Immediately after,\nops_free_list() frees the per-net state while concurrent packets might\nstill be executing nf_log_packet() under rcu_read_lock().\"\n\nClear the pointer via .pre_exit to make sure rcu readers have completed\nbefore pernet storage is free\u0027d.  The change in nf_log_syslog.c is only\ndone for consistency: it doesn\u0027t use pernet data."
          }
        ],
        "id": "CVE-2026-93288",
        "lastModified": "2026-09-25T13:17:18.433",
        "metrics": {
          "cvssMetricV31": [
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                "attackVector": "LOCAL",
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                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-09-24T17:17:10.070",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
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    "suse_vex": {
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      "current_release_date": "2026-09-25T23:49:11Z",
      "cve": "CVE-2026-93288",
      "id": "CVE-2026-93288",
      "initial_release_date": "2026-09-25T23:49:11Z",
      "product_status:known_affected": "341",
      "product_status:known_not_affected": "6",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-93288",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-93288.json",
      "version": "2"
    }
  }
}



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