github - ghsa-wxqp-f8fg-rxmv

GHSA-WXQP-F8FG-RXMV

Vulnerability from github – Published: 2025-12-04 18:30 – Updated: 2025-12-04 18:30

Details

In the Linux kernel, the following vulnerability has been resolved:

xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added

In commit b441cf3f8c4b ("xfrm: delete x->tunnel as we delete x"), I missed the case where state creation fails between full initialization (->init_state has been called) and being inserted on the lists.

In this situation, ->init_state has been called, so for IPcomp tunnels, the fallback tunnel has been created and added onto the lists, but the user state never gets added, because we fail before that. The user state doesn't go through __xfrm_state_delete, so we don't call xfrm_state_delete_tunnel for those states, and we end up leaking the FB tunnel.

There are several codepaths affected by this: the add/update paths, in both net/key and xfrm, and the migrate code (xfrm_migrate, xfrm_state_migrate). A "proper" rollback of the init_state work would probably be doable in the add/update code, but for migrate it gets more complicated as multiple states may be involved.

At some point, the new (not-inserted) state will be destroyed, so call xfrm_state_delete_tunnel during xfrm_state_gc_destroy. Most states will have their fallback tunnel cleaned up during __xfrm_state_delete, which solves the issue that b441cf3f8c4b (and other patches before it) aimed at. All states (including FB tunnels) will be removed from the lists once xfrm_state_fini has called flush_work(&xfrm_state_gc_work).

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{
  "affected": [],
  "aliases": [
    "CVE-2025-40256"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-04T16:16:19Z",
    "severity": null
  },
  "details": "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-\u003etunnel as we delete x\"), I\nmissed the case where state creation fails between full\ninitialization (-\u003einit_state has been called) and being inserted on\nthe lists.\n\nIn this situation, -\u003einit_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\u0027t go through __xfrm_state_delete, so we\ndon\u0027t 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(\u0026xfrm_state_gc_work).",
  "id": "GHSA-wxqp-f8fg-rxmv",
  "modified": "2025-12-04T18:30:53Z",
  "published": "2025-12-04T18:30:53Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40256"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/10deb69864840ccf96b00ac2ab3a2055c0c04721"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d6fe5c740c573af10943b8353992e1325cdb2715"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2025-40256 (GCVE-0-2025-40256)

Vulnerability from cvelistv5 – Published: 2025-12-04 16:08 – Updated: 2025-12-04 16:08

Summary

In the Linux kernel, the following vulnerability has been resolved: xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added In commit b441cf3f8c4b ("xfrm: delete x->tunnel as we delete x"), I missed the case where state creation fails between full initialization (->init_state has been called) and being inserted on the lists. In this situation, ->init_state has been called, so for IPcomp tunnels, the fallback tunnel has been created and added onto the lists, but the user state never gets added, because we fail before that. The user state doesn't go through __xfrm_state_delete, so we don't call xfrm_state_delete_tunnel for those states, and we end up leaking the FB tunnel. There are several codepaths affected by this: the add/update paths, in both net/key and xfrm, and the migrate code (xfrm_migrate, xfrm_state_migrate). A "proper" rollback of the init_state work would probably be doable in the add/update code, but for migrate it gets more complicated as multiple states may be involved. At some point, the new (not-inserted) state will be destroyed, so call xfrm_state_delete_tunnel during xfrm_state_gc_destroy. Most states will have their fallback tunnel cleaned up during __xfrm_state_delete, which solves the issue that b441cf3f8c4b (and other patches before it) aimed at. All states (including FB tunnels) will be removed from the lists once xfrm_state_fini has called flush_work(&xfrm_state_gc_work).

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/d6fe5c740c573af10…
	https://git.kernel.org/stable/c/10deb69864840ccf9…

Impacted products

Vendor

Product

Version

Linux

Affected: b441cf3f8c4b8576639d20c8eb4aa32917602ecd , < d6fe5c740c573af10943b8353992e1325cdb2715 (git)
Affected: b441cf3f8c4b8576639d20c8eb4aa32917602ecd , < 10deb69864840ccf96b00ac2ab3a2055c0c04721 (git)

Linux

Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.17.10 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/xfrm/xfrm_state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d6fe5c740c573af10943b8353992e1325cdb2715",
              "status": "affected",
              "version": "b441cf3f8c4b8576639d20c8eb4aa32917602ecd",
              "versionType": "git"
            },
            {
              "lessThan": "10deb69864840ccf96b00ac2ab3a2055c0c04721",
              "status": "affected",
              "version": "b441cf3f8c4b8576639d20c8eb4aa32917602ecd",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/xfrm/xfrm_state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17.10",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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-\u003etunnel as we delete x\"), I\nmissed the case where state creation fails between full\ninitialization (-\u003einit_state has been called) and being inserted on\nthe lists.\n\nIn this situation, -\u003einit_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\u0027t go through __xfrm_state_delete, so we\ndon\u0027t 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(\u0026xfrm_state_gc_work)."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-04T16:08:17.756Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d6fe5c740c573af10943b8353992e1325cdb2715"
        },
        {
          "url": "https://git.kernel.org/stable/c/10deb69864840ccf96b00ac2ab3a2055c0c04721"
        }
      ],
      "title": "xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40256",
    "datePublished": "2025-12-04T16:08:17.756Z",
    "dateReserved": "2025-04-16T07:20:57.181Z",
    "dateUpdated": "2025-12-04T16:08:17.756Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-WXQP-F8FG-RXMV

CVE-2025-40256 (GCVE-0-2025-40256)

Tags

Sightings

Nomenclature