CVE-2026-97949 (GCVE-0-2026-97949)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:22 – Updated: 2026-09-25 10:22
VLAI
Title
configfs: unhash the dentry before dropping the item in rmdir
Summary
In the Linux kernel, the following vulnerability has been resolved: configfs: unhash the dentry before dropping the item in rmdir configfs_get_config_item() treats a hashed dentry as proof that sd->s_element is a live config_item. configfs_rmdir() breaks that: simple_rmdir() leaves the dentry hashed, the last reference to the item is dropped right after, and the dentry is only unhashed by d_delete() once ->rmdir() has returned. configfs_symlink() resolves its target holding no lock on it, so get_target() can land in that window: BUG: KASAN: slab-use-after-free in config_item_get+0x26/0x90 get_target fs/configfs/symlink.c:128 [inline] configfs_symlink+0x4ab/0x1030 fs/configfs/symlink.c:185 Unhash in configfs_remove_dir(), while the item is still guaranteed to be there. A reference obtained just before that stays harmless, as create_link() rechecks CONFIGFS_USET_DROPPING, already set by configfs_detach_prep(). Both configfs_unregister_subsystem() paths d_drop() after detaching, so this only makes rmdir match them.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 7063fbf2261194f72ee75afca67b3b38b554b5fa , < 5d7cbfb65e47cc71d5d94d87d5d0d1679080f3eb (git)
Affected: 7063fbf2261194f72ee75afca67b3b38b554b5fa , < 925d8564f1b2d9b46c5ab63b9bc942cea006da9b (git)
Affected: 7063fbf2261194f72ee75afca67b3b38b554b5fa , < f06c2d26d1999d37e93299db0ecead04ca7d0b9f (git)
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Linux Linux Affected: 2.6.16
Unaffected: 0 , < 2.6.16 (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/configfs/dir.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "2.6.16"
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              "version": "0",
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              "versionType": "semver"
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            {
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              "versionType": "semver"
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              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
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        }
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                {
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nconfigfs: unhash the dentry before dropping the item in rmdir\n\nconfigfs_get_config_item() treats a hashed dentry as proof that\nsd-\u003es_element is a live config_item.  configfs_rmdir() breaks that:\nsimple_rmdir() leaves the dentry hashed, the last reference to the item is\ndropped right after, and the dentry is only unhashed by d_delete() once\n-\u003ermdir() has returned.  configfs_symlink() resolves its target holding no\nlock on it, so get_target() can land in that window:\n\n  BUG: KASAN: slab-use-after-free in config_item_get+0x26/0x90\n   get_target fs/configfs/symlink.c:128 [inline]\n   configfs_symlink+0x4ab/0x1030 fs/configfs/symlink.c:185\n\nUnhash in configfs_remove_dir(), while the item is still guaranteed to be\nthere.  A reference obtained just before that stays harmless, as\ncreate_link() rechecks CONFIGFS_USET_DROPPING, already set by\nconfigfs_detach_prep().  Both configfs_unregister_subsystem() paths\nd_drop() after detaching, so this only makes rmdir match them."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T10:22:58.375Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/5d7cbfb65e47cc71d5d94d87d5d0d1679080f3eb"
        },
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          "url": "https://git.kernel.org/stable/c/925d8564f1b2d9b46c5ab63b9bc942cea006da9b"
        },
        {
          "url": "https://git.kernel.org/stable/c/f06c2d26d1999d37e93299db0ecead04ca7d0b9f"
        }
      ],
      "title": "configfs: unhash the dentry before dropping the item in rmdir",
      "x_generator": {
        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97949",
    "datePublished": "2026-09-25T10:22:58.375Z",
    "dateReserved": "2026-09-25T10:18:58.205Z",
    "dateUpdated": "2026-09-25T10:22:58.375Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-97949",
      "date": "2026-09-28",
      "epss": "0.00166",
      "percentile": "0.05182"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-27T23:16:10.000Z",
      "cve": "CVE-2026-97949",
      "id": "msrc_CVE-2026-97949",
      "initial_release_date": "2026-09-27T23:16:10.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "configfs: unhash the dentry before dropping the item in rmdir",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-97949.json",
      "version": "1"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
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                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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                  },
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                    "versionType": "semver"
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                    "versionType": "semver"
                  },
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                    "versionType": "original_commit_for_fix"
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                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nconfigfs: unhash the dentry before dropping the item in rmdir\n\nconfigfs_get_config_item() treats a hashed dentry as proof that\nsd-\u003es_element is a live config_item.  configfs_rmdir() breaks that:\nsimple_rmdir() leaves the dentry hashed, the last reference to the item is\ndropped right after, and the dentry is only unhashed by d_delete() once\n-\u003ermdir() has returned.  configfs_symlink() resolves its target holding no\nlock on it, so get_target() can land in that window:\n\n  BUG: KASAN: slab-use-after-free in config_item_get+0x26/0x90\n   get_target fs/configfs/symlink.c:128 [inline]\n   configfs_symlink+0x4ab/0x1030 fs/configfs/symlink.c:185\n\nUnhash in configfs_remove_dir(), while the item is still guaranteed to be\nthere.  A reference obtained just before that stays harmless, as\ncreate_link() rechecks CONFIGFS_USET_DROPPING, already set by\nconfigfs_detach_prep().  Both configfs_unregister_subsystem() paths\nd_drop() after detaching, so this only makes rmdir match them."
          }
        ],
        "id": "CVE-2026-97949",
        "lastModified": "2026-09-25T11:17:22.453",
        "metrics": {},
        "published": "2026-09-25T11:17:22.453",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/5d7cbfb65e47cc71d5d94d87d5d0d1679080f3eb"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/f06c2d26d1999d37e93299db0ecead04ca7d0b9f"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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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.
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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.