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netfilter: nf_tables: don't skip expired elements during walk

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: don't skip expired elements during walk There is an asymmetry between commit/abort and preparation phase if the following conditions are met: 1. set is a verdict map ("1.2.3.4 : jump foo") 2. timeouts are enabled In this case, following sequence is problematic: 1. element E in set S refers to chain C 2. userspace requests removal of set S 3. kernel does a set walk to decrement chain->use count for all elements from preparation phase 4. kernel does another set walk to remove elements from the commit phase (or another walk to do a chain->use increment for all elements from abort phase) If E has already expired in 1), it will be ignored during list walk, so its use count won't have been changed. Then, when set is culled, ->destroy callback will zap the element via nf_tables_set_elem_destroy(), but this function is only safe for elements that have been deactivated earlier from the preparation phase: lack of earlier deactivate removes the element but leaks the chain use count, which results in a WARN splat when the chain gets removed later, plus a leak of the nft_chain structure. Update pipapo_get() not to skip expired elements, otherwise flush command reports bogus ENOENT errors.

Products
Kernel
Affected versions
Not specified
Fixed versions
4.19.316, 5.10.198, 5.15.134, 5.4.262, 6.1.56, 6.4.11
CVEs
CVE-2023-52924
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 16:18 UTC · Revision 1

Source evidence

netfilter: nf_tables: don't skip expired elements during walk

core-osv · Original source

Published 5 Feb 2025, 09:07 UTC

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: don't skip expired elements during walk There is an asymmetry between commit/abort and preparation phase if the following conditions are met: 1. set is a verdict map ("1.2.3.4 : jump foo") 2. timeouts are enabled In this case, following sequence is problematic: 1. element E in set S refers to chain C 2. userspace requests removal of set S 3. kernel does a set walk to decrement chain->use count for all elements from preparation phase 4. kernel does another set walk to remove elements from the commit phase (or another walk to do a chain->use increment for all elements from abort phase) If E has already expired in 1), it will be ignored during list walk, so its use count won't have been changed. Then, when set is culled, ->destroy callback will zap the element via nf_tables_set_elem_destroy(), but this function is only safe for elements that have been deactivated earlier from the preparation phase: lack of earlier deactivate removes the element but leaks the chain use count, which results in a WARN splat when the chain gets removed later, plus a leak of the nft_chain structure. Update pipapo_get() not to skip expired elements, otherwise flush command reports bogus ENOENT errors.

osv:CVE-2023-52924

Kernel

Fixed versions: 4.19.316, 5.4.262, 5.10.198, 5.15.134, 6.1.56, 6.4.11

Complete source record
{
  "id": "13f8ea3679ef4a5582806a483535fef72ef569c349f570db64f2b8267c51a157",
  "url": "https://osv.dev/vulnerability/CVE-2023-52924",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "netfilter: nf_tables: don't skip expired elements during walk",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: don't skip expired elements during walk There is an asymmetry between commit/abort and preparation phase if the following conditions are met: 1. set is a verdict map (\"1.2.3.4 : jump foo\") 2. timeouts are enabled In this case, following sequence is problematic: 1. element E in set S refers to chain C 2. userspace requests removal of set S 3. kernel does a set walk to decrement chain->use count for all elements from preparation phase 4. kernel does another set walk to remove elements from the commit phase (or another walk to do a chain->use increment for all elements from abort phase) If E has already expired in 1), it will be ignored during list walk, so its use count won't have been changed. Then, when set is culled, ->destroy callback will zap the element via nf_tables_set_elem_destroy(), but this function is only safe for elements that have been deactivated earlier from the preparation phase: lack of earlier deactivate removes the element but leaks the chain use count, which results in a WARN splat when the chain gets removed later, plus a leak of the nft_chain structure. Update pipapo_get() not to skip expired elements, otherwise flush command reports bogus ENOENT errors.",
    "evidence": "osv:CVE-2023-52924",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.19.316",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.4.262",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.10.198",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.134",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.56",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.4.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2023-52924",
      "aliases": [
        "CVE-2023-52924"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "9d0982927e79049675cb6c6c04a0ebb3dad5a434"
                },
                {
                  "fixed": "94313a196b44184b5b52c1876da6a537701b425a"
                },
                {
                  "fixed": "1da4874d05da1526b11b82fc7f3c7ac38749ddf8"
                },
                {
                  "fixed": "b15ea4017af82011dd55225ce77cce3d4dfc169c"
                },
                {
                  "fixed": "7c7e658a36f8b1522bd3586d8137e5f93a25ddc5"
                },
                {
                  "fixed": "59dab3bf0b8fc08eb802721c0532f13dd89209b8"
                },
                {
                  "fixed": "bd156ce9553dcaf2d6ee2c825d1a5a1718e86524"
                },
                {
                  "fixed": "24138933b97b055d486e8064b4a1721702442a9b"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-52924.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.1.0"
                },
                {
                  "fixed": "4.19.316"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.20.0"
                },
                {
                  "fixed": "5.4.262"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.5.0"
                },
                {
                  "fixed": "5.10.198"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.134"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.56"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.4.11"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-52924.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.661654118Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1da4874d05da1526b11b82fc7f3c7ac38749ddf8",
        "https://git.kernel.org/stable/c/24138933b97b055d486e8064b4a1721702442a9b",
        "https://git.kernel.org/stable/c/59dab3bf0b8fc08eb802721c0532f13dd89209b8",
        "https://git.kernel.org/stable/c/7c7e658a36f8b1522bd3586d8137e5f93a25ddc5",
        "https://git.kernel.org/stable/c/94313a196b44184b5b52c1876da6a537701b425a",
        "https://git.kernel.org/stable/c/b15ea4017af82011dd55225ce77cce3d4dfc169c",
        "https://git.kernel.org/stable/c/bd156ce9553dcaf2d6ee2c825d1a5a1718e86524",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/52xxx/CVE-2023-52924.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-52924",
        "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/2023/52xxx/CVE-2023-52924.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-52924",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 504586,
  "published_at": "2025-02-05T09:07:55.418+00:00"
}