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netfilter: nfnetlink_osf: fix potential NULL dereference in ttl check

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_osf: fix potential NULL dereference in ttl check The nf_osf_ttl() function accessed skb->dev to perform a local interface address lookup without verifying that the device pointer was valid. Additionally, the implementation utilized an in_dev_for_each_ifa_rcu loop to match the packet source address against local interface addresses. It assumed that packets from the same subnet should not see a decrement on the initial TTL. A packet might appear it is from the same subnet but it actually isn't especially in modern environments with containers and virtual switching. Remove the device dereference and interface loop. Replace the logic with a switch statement that evaluates the TTL according to the ttl_check.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.258, 5.15.209, 6.1.175, 6.12.91, 6.18.33, 6.6.141, 7.0.10
CVEs
CVE-2026-52998
Confirmed fixed CVEs
Not specified
Updated in this feed
6 Nov 2026, 00:10 UTC · Revision 1

Source evidence

netfilter: nfnetlink_osf: fix potential NULL dereference in ttl check

core-osv · Original source

Published 24 Jun 2026, 16:29 UTC

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_osf: fix potential NULL dereference in ttl check The nf_osf_ttl() function accessed skb->dev to perform a local interface address lookup without verifying that the device pointer was valid. Additionally, the implementation utilized an in_dev_for_each_ifa_rcu loop to match the packet source address against local interface addresses. It assumed that packets from the same subnet should not see a decrement on the initial TTL. A packet might appear it is from the same subnet but it actually isn't especially in modern environments with containers and virtual switching. Remove the device dereference and interface loop. Replace the logic with a switch statement that evaluates the TTL according to the ttl_check.

osv:CVE-2026-52998

Kernel

Fixed versions: 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33, 7.0.10

Complete source record
{
  "id": "888e2b3c6009ee3bfc6fa62c7e22817994d39edf3e4754ad44b714e6b11dae2e",
  "url": "https://osv.dev/vulnerability/CVE-2026-52998",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "netfilter: nfnetlink_osf: fix potential NULL dereference in ttl check",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_osf: fix potential NULL dereference in ttl check The nf_osf_ttl() function accessed skb->dev to perform a local interface address lookup without verifying that the device pointer was valid. Additionally, the implementation utilized an in_dev_for_each_ifa_rcu loop to match the packet source address against local interface addresses. It assumed that packets from the same subnet should not see a decrement on the initial TTL. A packet might appear it is from the same subnet but it actually isn't especially in modern environments with containers and virtual switching. Remove the device dereference and interface loop. Replace the logic with a switch statement that evaluates the TTL according to the ttl_check.",
    "evidence": "osv:CVE-2026-52998",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.258",
            "evidence": "/affected/1/ranges"
          },
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            "value": "5.15.209",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.175",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.141",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.91",
            "evidence": "/affected/1/ranges"
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          {
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            "value": "7.0.10",
            "evidence": "/affected/1/ranges"
          }
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        "affected_versions": []
      }
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    "severity": "high",
    "structured": {
      "id": "CVE-2026-52998",
      "aliases": [
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      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
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      "affected": [
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                {
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        {
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                  "introduced": "2.6.31"
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            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
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                {
                  "fixed": "5.15.209"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
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                  "fixed": "6.1.175"
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            {
              "type": "ECOSYSTEM",
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                  "introduced": "6.2.0"
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            {
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            },
            {
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                  "introduced": "6.13.0"
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                {
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.19.0"
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52998.json"
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        }
      ],
      "modified": "2026-10-28T02:30:45.150954403Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-019113.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-457936.html",
        "https://git.kernel.org/stable/c/5d05de2f0928d81309a815ecc76d1a3ad72cbc16",
        "https://git.kernel.org/stable/c/711987ba281fd806322a7cd244e98e2a81903114",
        "https://git.kernel.org/stable/c/79b90a96688e521771fa6ed3dc7864b76b8df293",
        "https://git.kernel.org/stable/c/83fc5dd63455a779ea2dd0f7ffee3c920919d80b",
        "https://git.kernel.org/stable/c/95be653a76793856ff8b2d8bd82c2943c23f5ca8",
        "https://git.kernel.org/stable/c/c996a90f3071cf43683e5423da31aadbe002b8b4",
        "https://git.kernel.org/stable/c/edc806f9122961f0d3819f7c69c14cccde31f277",
        "https://git.kernel.org/stable/c/f4de0777e4554a7de19c920accde6319dd530782",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52998.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-52998",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52998.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-52998",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 513359,
  "published_at": "2026-06-24T16:29:10.874+00:00"
}