Vulnerability-Lookup

GHSA-25RG-2WRR-633H

Vulnerability from github – Published: 2025-10-24 12:30 – Updated: 2026-07-30 06:32

Details

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

ipvs: Defer ip_vs_ftp unregister during netns cleanup

On the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp before connections with valid cp->app pointers are flushed, leading to a use-after-free.

Fix this by introducing a global exiting_module flag, set to true in ip_vs_ftp_exit() before unregistering the pernet subsystem. In __ip_vs_ftp_exit(), skip ip_vs_ftp unregister if called during netns cleanup (when exiting_module is false) and defer it to __ip_vs_cleanup_batch(), which unregisters all apps after all connections are flushed. If called during module exit, unregister ip_vs_ftp immediately.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2025-40018"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-10-24T12:15:37Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: Defer ip_vs_ftp unregister during netns cleanup\n\nOn the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp\nbefore connections with valid cp-\u003eapp pointers are flushed, leading to a\nuse-after-free.\n\nFix this by introducing a global `exiting_module` flag, set to true in\nip_vs_ftp_exit() before unregistering the pernet subsystem. In\n__ip_vs_ftp_exit(), skip ip_vs_ftp unregister if called during netns\ncleanup (when exiting_module is false) and defer it to\n__ip_vs_cleanup_batch(), which unregisters all apps after all connections\nare flushed. If called during module exit, unregister ip_vs_ftp\nimmediately.",
  "id": "GHSA-25rg-2wrr-633h",
  "modified": "2026-07-30T06:32:12Z",
  "published": "2025-10-24T12:30:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40018"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/134121bfd99a06d44ef5ba15a9beb075297c0821"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1d79471414d7b9424d699afff2aa79fff322f52d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/421b1ae1574dfdda68b835c15ac4921ec0030182"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/53717f8a4347b78eac6488072ad8e5adbaff38d9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8a6ecab3847c213ce2855b0378e63ce839085de3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8cbe2a21d85727b66d7c591fd5d83df0d8c4f757"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a343811ef138a265407167294275201621e9ebb2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dc1a481359a72ee7e548f1f5da671282a7c13b8f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2025-40018 (GCVE-0-2025-40018)

Vulnerability from cvelistv5 – Published: 2025-10-24 11:44 – Updated: 2026-08-05 12:07

Title

ipvs: Defer ip_vs_ftp unregister during netns cleanup

Summary

In the Linux kernel, the following vulnerability has been resolved: ipvs: Defer ip_vs_ftp unregister during netns cleanup On the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp before connections with valid cp->app pointers are flushed, leading to a use-after-free. Fix this by introducing a global `exiting_module` flag, set to true in ip_vs_ftp_exit() before unregistering the pernet subsystem. In __ip_vs_ftp_exit(), skip ip_vs_ftp unregister if called during netns cleanup (when exiting_module is false) and defer it to __ip_vs_cleanup_batch(), which unregisters all apps after all connections are flushed. If called during module exit, unregister ip_vs_ftp immediately.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux

References

8 references

URL	Tags
https://git.kernel.org/stable/c/8a6ecab3847c213ce…
https://git.kernel.org/stable/c/421b1ae1574dfdda6…
https://git.kernel.org/stable/c/1d79471414d7b9424…
https://git.kernel.org/stable/c/53717f8a4347b78ea…
https://git.kernel.org/stable/c/8cbe2a21d85727b66…
https://git.kernel.org/stable/c/dc1a481359a72ee7e…
https://git.kernel.org/stable/c/a343811ef138a2654…
https://git.kernel.org/stable/c/134121bfd99a06d44…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 61b1ab4583e275af216c8454b9256de680499b19 , < 8a6ecab3847c213ce2855b0378e63ce839085de3 (git) Affected: 61b1ab4583e275af216c8454b9256de680499b19 , < 421b1ae1574dfdda68b835c15ac4921ec0030182 (git) Affected: 61b1ab4583e275af216c8454b9256de680499b19 , < 1d79471414d7b9424d699afff2aa79fff322f52d (git) Affected: 61b1ab4583e275af216c8454b9256de680499b19 , < 53717f8a4347b78eac6488072ad8e5adbaff38d9 (git) Affected: 61b1ab4583e275af216c8454b9256de680499b19 , < 8cbe2a21d85727b66d7c591fd5d83df0d8c4f757 (git) Affected: 61b1ab4583e275af216c8454b9256de680499b19 , < dc1a481359a72ee7e548f1f5da671282a7c13b8f (git) Affected: 61b1ab4583e275af216c8454b9256de680499b19 , < a343811ef138a265407167294275201621e9ebb2 (git) Affected: 61b1ab4583e275af216c8454b9256de680499b19 , < 134121bfd99a06d44ef5ba15a9beb075297c0821 (git)
Linux	Linux	Affected: 2.6.39 Unaffected: 0 , < 2.6.39 (semver) Unaffected: 5.4.301 , ≤ 5.4.* (semver) Unaffected: 5.10.246 , ≤ 5.10.* (semver) Unaffected: 5.15.195 , ≤ 5.15.* (semver) Unaffected: 6.1.156 , ≤ 6.1.* (semver) Unaffected: 6.6.112 , ≤ 6.6.* (semver) Unaffected: 6.12.53 , ≤ 6.12.* (semver) Unaffected: 6.17.3 , ≤ 6.17.* (semver) Unaffected: 6.18 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/ipvs/ip_vs_ftp.c"
          ],
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            {
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            {
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              "status": "affected",
              "version": "61b1ab4583e275af216c8454b9256de680499b19",
              "versionType": "git"
            },
            {
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              "versionType": "git"
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              "versionType": "git"
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            {
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            },
            {
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.39"
            },
            {
              "lessThan": "2.6.39",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.301",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.246",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.195",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.156",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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                  "vulnerable": true
                },
                {
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                },
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18",
                  "versionStartIncluding": "2.6.39",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: Defer ip_vs_ftp unregister during netns cleanup\n\nOn the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp\nbefore connections with valid cp-\u003eapp pointers are flushed, leading to a\nuse-after-free.\n\nFix this by introducing a global `exiting_module` flag, set to true in\nip_vs_ftp_exit() before unregistering the pernet subsystem. In\n__ip_vs_ftp_exit(), skip ip_vs_ftp unregister if called during netns\ncleanup (when exiting_module is false) and defer it to\n__ip_vs_cleanup_batch(), which unregisters all apps after all connections\nare flushed. If called during module exit, unregister ip_vs_ftp\nimmediately."
        }
      ],
      "metrics": [
        {
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            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
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            {
              "lang": "en",
              "value": "AV:L - The use-after-free is triggered by network namespace teardown, which requires local access (unshare/exit of a netns, or `ip netns del`); while a remote client can populate the FTP-bound IPVS connections through the load balancer, the free-and-use sequence itself is driven locally.\nAC:L - The bad ordering is deterministic \u2014 pernet exit callbacks always run in reverse registration order, so `__ip_vs_ftp_exit()` always precedes the connection flush \u2014 and the attacker controls both the connection creation and the netns destruction, with ordinary heap grooming sufficing to reclaim the freed `ip_vs_app` objects.\nPR:L - Configuring the IPVS FTP virtual service needs CAP_NET_ADMIN, but `do_ip_vs_set_ctl()` checks `ns_capable(net-\u003euser_ns, CAP_NET_ADMIN)` and IPVS was explicitly made usable in non-init user namespaces, so an unprivileged local user obtains it with `unshare -Urn`.\nUI:N - The attacker performs the entire sequence \u2014 namespace creation, IPVS service setup, connection establishment and namespace teardown \u2014 with no action from any other user.\nS:U - The corruption and any resulting privilege escalation stay within the kernel\u0027s own security authority; no VM, IOMMU, or other trust boundary is crossed.\nC:H - `ip_vs_unbind_app()` dereferences the freed `inc` and the already-kfree()\u0027d `inc-\u003eapp`, so reclaiming those slab objects lets an attacker read and leak kernel heap contents and pointers.\nI:H - The use-after-free yields a write primitive (`atomic_dec(\u0026inc-\u003eusecnt)` and `module_put()` through a dangling `inc-\u003eapp` pointer) plus an indirect call through the freed `inc-\u003edone_conn`/`unbind_conn` function pointers, which is a control-flow hijack primitive after heap spraying.\nA:H - Even unexploited, the use-after-free calls a function pointer from reclaimed memory and corrupts refcounts during netns cleanup, reliably producing a kernel oops or panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:07:05.588Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/dc1a481359a72ee7e548f1f5da671282a7c13b8f"
        },
        {
          "url": "https://git.kernel.org/stable/c/a343811ef138a265407167294275201621e9ebb2"
        },
        {
          "url": "https://git.kernel.org/stable/c/134121bfd99a06d44ef5ba15a9beb075297c0821"
        }
      ],
      "title": "ipvs: Defer ip_vs_ftp unregister during netns cleanup",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40018",
    "datePublished": "2025-10-24T11:44:28.955Z",
    "dateReserved": "2025-04-16T07:20:57.152Z",
    "dateUpdated": "2026-08-05T12:07:05.588Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

GHSA-25RG-2WRR-633H

CVE-2025-40018 (GCVE-0-2025-40018)

Tags

Sightings

Nomenclature