CVE-2026-23405 (GCVE-0-2026-23405)

Vulnerability from cvelistv5 – Published: 2026-04-01 08:36 – Updated: 2026-04-01 08:36
VLAI?
Title
apparmor: fix: limit the number of levels of policy namespaces
Summary
In the Linux kernel, the following vulnerability has been resolved: apparmor: fix: limit the number of levels of policy namespaces Currently the number of policy namespaces is not bounded relying on the user namespace limit. However policy namespaces aren't strictly tied to user namespaces and it is possible to create them and nest them arbitrarily deep which can be used to exhaust system resource. Hard cap policy namespaces to the same depth as user namespaces.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: c88d4c7b049e87998ac0a9f455aa545cc895ef92 , < 3f8699b3ee0c04b4b9bc27b82cd89a40e81e1d2e (git)
Affected: c88d4c7b049e87998ac0a9f455aa545cc895ef92 , < 853ce31ca72097d23991a06876a2ccb5cb64b603 (git)
Affected: c88d4c7b049e87998ac0a9f455aa545cc895ef92 , < d42b2b6bb77ca40ee34ab74ad79305840b5f315d (git)
Affected: c88d4c7b049e87998ac0a9f455aa545cc895ef92 , < 7b6495ead2c611647f6b11441a852324e3eb8616 (git)
Affected: c88d4c7b049e87998ac0a9f455aa545cc895ef92 , < 306039414932c80f8420695a24d4fe10c84ccfb2 (git)
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    Linux Linux Affected: 2.6.36
Unaffected: 0 , < 2.6.36 (semver)
Unaffected: 6.6.130 , ≤ 6.6.* (semver)
Unaffected: 6.12.77 , ≤ 6.12.* (semver)
Unaffected: 6.18.18 , ≤ 6.18.* (semver)
Unaffected: 6.19.8 , ≤ 6.19.* (semver)
Unaffected: 7.0-rc4 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "security/apparmor/include/policy_ns.h",
            "security/apparmor/policy_ns.c"
          ],
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          "vendor": "Linux",
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            },
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              "status": "unaffected",
              "version": "6.18.18",
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              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0-rc4",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: fix: limit the number of levels of policy namespaces\n\nCurrently the number of policy namespaces is not bounded relying on\nthe user namespace limit. However policy namespaces aren\u0027t strictly\ntied to user namespaces and it is possible to create them and nest\nthem arbitrarily deep which can be used to exhaust system resource.\n\nHard cap policy namespaces to the same depth as user namespaces."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-01T08:36:35.697Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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        {
          "url": "https://git.kernel.org/stable/c/306039414932c80f8420695a24d4fe10c84ccfb2"
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      ],
      "title": "apparmor: fix: limit the number of levels of policy namespaces",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23405",
    "datePublished": "2026-04-01T08:36:35.697Z",
    "dateReserved": "2026-01-13T15:37:46.012Z",
    "dateUpdated": "2026-04-01T08:36:35.697Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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  }
}


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  • 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.
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  • 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.



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