FKIE_CVE-2025-40215

Vulnerability from fkie_nvd - Published: 2025-12-04 13:15 - Updated: 2026-10-19 21:10
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: xfrm: delete x->tunnel as we delete x The ipcomp fallback tunnels currently get deleted (from the various lists and hashtables) as the last user state that needed that fallback is destroyed (not deleted). If a reference to that user state still exists, the fallback state will remain on the hashtables/lists, triggering the WARN in xfrm_state_fini. Because of those remaining references, the fix in commit f75a2804da39 ("xfrm: destroy xfrm_state synchronously on net exit path") is not complete. We recently fixed one such situation in TCP due to defered freeing of skbs (commit 9b6412e6979f ("tcp: drop secpath at the same time as we currently drop dst")). This can also happen due to IP reassembly: skbs with a secpath remain on the reassembly queue until netns destruction. If we can't guarantee that the queues are flushed by the time xfrm_state_fini runs, there may still be references to a (user) xfrm_state, preventing the timely deletion of the corresponding fallback state. Instead of chasing each instance of skbs holding a secpath one by one, this patch fixes the issue directly within xfrm, by deleting the fallback state as soon as the last user state depending on it has been deleted. Destruction will still happen when the final reference is dropped. A separate lockdep class for the fallback state is required since we're going to lock x->tunnel while x is locked.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0da961fa46da1b37ef868d9b603bd202136f8f8e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1b28a7fae0128fa140a7dccd995182ff6cd1c67b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4b2c17d0f9be8b58bb30468bc81a4b61c985b04e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b441cf3f8c4b8576639d20c8eb4aa32917602ecd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d0e0d1097118461463b76562c7ebaabaa5b90b13
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dc3636912d41770466543623cb76e7b88fdb42c7
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/xfrm.h",
            "net/ipv4/ipcomp.c",
            "net/ipv6/ipcomp6.c",
            "net/ipv6/xfrm6_tunnel.c",
            "net/xfrm/xfrm_ipcomp.c",
            "net/xfrm/xfrm_state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "1b28a7fae0128fa140a7dccd995182ff6cd1c67b",
              "status": "affected",
              "version": "9d4139c76905833afcb77fe8ccc17f302a0eb9ab",
              "versionType": "git"
            },
            {
              "lessThan": "4b2c17d0f9be8b58bb30468bc81a4b61c985b04e",
              "status": "affected",
              "version": "9d4139c76905833afcb77fe8ccc17f302a0eb9ab",
              "versionType": "git"
            },
            {
              "lessThan": "0da961fa46da1b37ef868d9b603bd202136f8f8e",
              "status": "affected",
              "version": "9d4139c76905833afcb77fe8ccc17f302a0eb9ab",
              "versionType": "git"
            },
            {
              "lessThan": "d0e0d1097118461463b76562c7ebaabaa5b90b13",
              "status": "affected",
              "version": "9d4139c76905833afcb77fe8ccc17f302a0eb9ab",
              "versionType": "git"
            },
            {
              "lessThan": "dc3636912d41770466543623cb76e7b88fdb42c7",
              "status": "affected",
              "version": "9d4139c76905833afcb77fe8ccc17f302a0eb9ab",
              "versionType": "git"
            },
            {
              "lessThan": "b441cf3f8c4b8576639d20c8eb4aa32917602ecd",
              "status": "affected",
              "version": "9d4139c76905833afcb77fe8ccc17f302a0eb9ab",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/net/xfrm.h",
            "net/ipv4/ipcomp.c",
            "net/ipv6/ipcomp6.c",
            "net/ipv6/xfrm6_tunnel.c",
            "net/xfrm/xfrm_ipcomp.c",
            "net/xfrm/xfrm_state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.29"
            },
            {
              "lessThan": "2.6.29",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.248",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.198",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.120",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.62",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.16",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: delete x-\u003etunnel as we delete x\n\nThe ipcomp fallback tunnels currently get deleted (from the various\nlists and hashtables) as the last user state that needed that fallback\nis destroyed (not deleted). If a reference to that user state still\nexists, the fallback state will remain on the hashtables/lists,\ntriggering the WARN in xfrm_state_fini. Because of those remaining\nreferences, the fix in commit f75a2804da39 (\"xfrm: destroy xfrm_state\nsynchronously on net exit path\") is not complete.\n\nWe recently fixed one such situation in TCP due to defered freeing of\nskbs (commit 9b6412e6979f (\"tcp: drop secpath at the same time as we\ncurrently drop dst\")). This can also happen due to IP reassembly: skbs\nwith a secpath remain on the reassembly queue until netns\ndestruction. If we can\u0027t guarantee that the queues are flushed by the\ntime xfrm_state_fini runs, there may still be references to a (user)\nxfrm_state, preventing the timely deletion of the corresponding\nfallback state.\n\nInstead of chasing each instance of skbs holding a secpath one by one,\nthis patch fixes the issue directly within xfrm, by deleting the\nfallback state as soon as the last user state depending on it has been\ndeleted. Destruction will still happen when the final reference is\ndropped.\n\nA separate lockdep class for the fallback state is required since\nwe\u0027re going to lock x-\u003etunnel while x is locked."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nxfrm: eliminar x-\u003etunnel a medida que eliminamos x\n\nLos t\u00faneles de respaldo ipcomp actualmente se eliminan (de las diversas listas y tablas hash) a medida que el \u00faltimo estado de usuario que necesitaba ese respaldo es destruido (no eliminado). Si una referencia a ese estado de usuario a\u00fan existe, el estado de respaldo permanecer\u00e1 en las tablas hash/listas, lo que activar\u00e1 la ADVERTENCIA en xfrm_state_fini. Debido a esas referencias restantes, la correcci\u00f3n en el commit f75a2804da39 (\u201cxfrm: destruir xfrm_state sincr\u00f3nicamente en la ruta de salida de red\u201d) no est\u00e1 completa.\n\nRecientemente corregimos una situaci\u00f3n similar en TCP debido a la liberaci\u00f3n diferida de skbs (commit 9b6412e6979f (\u201ctcp: eliminar secpath al mismo tiempo que actualmente eliminamos dst\u201d)). Esto tambi\u00e9n puede ocurrir debido al reensamblaje de IP: los skbs con un secpath permanecen en la cola de reensamblaje hasta la destrucci\u00f3n de netns. Si no podemos garantizar que las colas se vac\u00eden para cuando se ejecute xfrm_state_fini, a\u00fan puede haber referencias a un xfrm_state (de usuario), impidiendo la eliminaci\u00f3n oportuna del estado de respaldo correspondiente.\n\nEn lugar de perseguir cada instancia de skbs que contiene un secpath una por una, este parche corrige el problema directamente dentro de xfrm, al eliminar el estado de respaldo tan pronto como el \u00faltimo estado de usuario que depend\u00eda de \u00e9l haya sido eliminado. La destrucci\u00f3n seguir\u00e1 ocurriendo cuando se elimine la referencia final.\n\nSe requiere una clase lockdep separada para el estado de respaldo ya que vamos a bloquear x-\u003etunnel mientras x est\u00e1 bloqueado."
    }
  ],
  "id": "CVE-2025-40215",
  "lastModified": "2026-10-19T21:10:00.160",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "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"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-40215",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-06-16T19:56:10.578142Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2025-12-04T13:15:48.473",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0da961fa46da1b37ef868d9b603bd202136f8f8e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1b28a7fae0128fa140a7dccd995182ff6cd1c67b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4b2c17d0f9be8b58bb30468bc81a4b61c985b04e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b441cf3f8c4b8576639d20c8eb4aa32917602ecd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d0e0d1097118461463b76562c7ebaabaa5b90b13"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dc3636912d41770466543623cb76e7b88fdb42c7"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Deferred"
}



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