CVE-2025-40256

{
  "id": "CVE-2025-40256",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2025-12-04T16:16:19.367",
  "lastModified": "2026-10-19T19:10:00.130",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added\n\nIn commit b441cf3f8c4b (\"xfrm: delete x->tunnel as we delete x\"), I\nmissed the case where state creation fails between full\ninitialization (->init_state has been called) and being inserted on\nthe lists.\n\nIn this situation, ->init_state has been called, so for IPcomp\ntunnels, the fallback tunnel has been created and added onto the\nlists, but the user state never gets added, because we fail before\nthat. The user state doesn't go through __xfrm_state_delete, so we\ndon't call xfrm_state_delete_tunnel for those states, and we end up\nleaking the FB tunnel.\n\nThere are several codepaths affected by this: the add/update paths, in\nboth net/key and xfrm, and the migrate code (xfrm_migrate,\nxfrm_state_migrate). A \"proper\" rollback of the init_state work would\nprobably be doable in the add/update code, but for migrate it gets\nmore complicated as multiple states may be involved.\n\nAt some point, the new (not-inserted) state will be destroyed, so call\nxfrm_state_delete_tunnel during xfrm_state_gc_destroy. Most states\nwill have their fallback tunnel cleaned up during __xfrm_state_delete,\nwhich solves the issue that b441cf3f8c4b (and other patches before it)\naimed at. All states (including FB tunnels) will be removed from the\nlists once xfrm_state_fini has called flush_work(&xfrm_state_gc_work)."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nxfrm: también llamar a xfrm_state_delete_tunnel en el momento de la destrucción para estados que nunca fueron añadidos\n\nEn el commit b441cf3f8c4b (“xfrm: eliminar x -> tunnel al eliminar x”), omití el caso en que la creación del estado falla entre la inicialización completa (se ha llamado a  -> init_state) y su inserción en las listas.\n\nEn esta situación, se ha llamado a  -> init_state, por lo tanto, para los túneles IPcomp, el túnel de respaldo ha sido creado y añadido a las listas, pero el estado de usuario nunca se añade, porque fallamos antes de eso. El estado de usuario no pasa por __xfrm_state_delete, por lo que no llamamos a xfrm_state_delete_tunnel para esos estados, y terminamos fugando el túnel FB.\n\nHay varias rutas de código afectadas por esto: las rutas de adición/actualización, tanto en net/key como en xfrm, y el código de migración (xfrm_migrate, xfrm_state_migrate). Una reversión “adecuada” del trabajo de init_state probablemente sería factible en el código de adición/actualización, pero para la migración se complica más ya que pueden estar involucrados múltiples estados.\n\nEn algún momento, el nuevo estado (no insertado) será destruido, así que se llama a xfrm_state_delete_tunnel durante xfrm_state_gc_destroy. La mayoría de los estados tendrán su túnel de respaldo limpiado durante __xfrm_state_delete, lo que resuelve el problema al que apuntaba b441cf3f8c4b (y otros parches anteriores). Todos los estados (incluidos los túneles FB) serán eliminados de las listas una vez que xfrm_state_fini haya llamado a flush_work(&xfrm_state_gc_work)."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "net/xfrm/xfrm_state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "1b28a7fae0128fa140a7dccd995182ff6cd1c67b",
              "lessThan": "57b72d74d4651dc19d046308a8304eb9abfe66ac",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "4b2c17d0f9be8b58bb30468bc81a4b61c985b04e",
              "lessThan": "1dad653643f28ccc89be93f9440b8804cded85b2",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "0da961fa46da1b37ef868d9b603bd202136f8f8e",
              "lessThan": "64441724387b4ac92f67ef51caaaeffe99c950d1",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "d0e0d1097118461463b76562c7ebaabaa5b90b13",
              "lessThan": "763e5c351206c1e4d910db4a1159053f6263689c",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "dc3636912d41770466543623cb76e7b88fdb42c7",
              "lessThan": "f7d879c19d306512c2e260f37e8a3e5c85e37c50",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "b441cf3f8c4b8576639d20c8eb4aa32917602ecd",
              "lessThan": "d6fe5c740c573af10943b8353992e1325cdb2715",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "b441cf3f8c4b8576639d20c8eb4aa32917602ecd",
              "lessThan": "10deb69864840ccf96b00ac2ab3a2055c0c04721",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "net/xfrm/xfrm_state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.16",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.16",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.17.10",
              "lessThanOrEqual": "6.17.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/10deb69864840ccf96b00ac2ab3a2055c0c04721",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1dad653643f28ccc89be93f9440b8804cded85b2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/57b72d74d4651dc19d046308a8304eb9abfe66ac",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/64441724387b4ac92f67ef51caaaeffe99c950d1",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/763e5c351206c1e4d910db4a1159053f6263689c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d6fe5c740c573af10943b8353992e1325cdb2715",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f7d879c19d306512c2e260f37e8a3e5c85e37c50",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}