CVE-2026-97594 (GCVE-0-2026-97594)
Vulnerability from cvelistv5
Published
2026-09-25 10:22
Modified
2026-10-21 12:53
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: landlock: Fix use-after-free of the source's parent directory current_check_refer_path() reads old_dentry->d_parent without holding a reference nor a lock on it, and then dereferences it in collect_domain_accesses() and in the audit record. A reference on a child does not pin its parent: __d_move() reassigns dentry->d_parent and drops the reference the child held on its former parent. hook_path_rename() is not affected because the rename path calls lock_rename() before the hook, so the source cannot be reparented under it. hook_path_link() has no such protection: filename_linkat() holds a reference on the source dentry but neither locks nor references its parent, so a concurrent rename(2) can reparent the source while security_path_link() runs, and the former parent can then be removed and freed while the hook walks it. A process can trigger this after entering a Landlock domain that handles at least one filesystem access right. The process can then race a linkat(2) loop against rename(2) and rmdir(2): BUG: KASAN: slab-use-after-free in collect_domain_accesses+0x278/0x290 Read of size 4 at addr ffff888160bd53f4 by task llrepro2/549 collect_domain_accesses+0x278/0x290 current_check_refer_path+0x952/0x1120 security_path_link+0x1be/0x320 filename_linkat+0x342/0x6d0 __x64_sys_linkat+0xfa/0x150 Freed by task 562: kmem_cache_free+0x139/0x4c0 i_callback+0x4b/0x80 rcu_core+0x7dc/0x10a0 Take a reference on the dentry selected as the source parent, using dget() for the common-mount-root case and dget_parent() otherwise. Release it after the hierarchy walk and synchronous audit logging. [mic: Clarify the caller, reachability, and reference handling]
References
Impacted products
Vendor Product Version
Linux Linux Version: b91c3e4ea756b12b7d992529226edce1cfd854d7
Version: b91c3e4ea756b12b7d992529226edce1cfd854d7
Version: b91c3e4ea756b12b7d992529226edce1cfd854d7
Version: b91c3e4ea756b12b7d992529226edce1cfd854d7
Version: b91c3e4ea756b12b7d992529226edce1cfd854d7
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "security/landlock/fs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "versionType": "git"
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            {
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              "versionType": "git"
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            {
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "security/landlock/fs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.19"
            },
            {
              "lessThan": "5.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.160",
                  "versionStartIncluding": "5.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.112",
                  "versionStartIncluding": "5.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "5.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
                  "versionStartIncluding": "5.19",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlandlock: Fix use-after-free of the source\u0027s parent directory\n\ncurrent_check_refer_path() reads old_dentry-\u003ed_parent without holding a\nreference nor a lock on it, and then dereferences it in\ncollect_domain_accesses() and in the audit record.\n\nA reference on a child does not pin its parent: __d_move() reassigns\ndentry-\u003ed_parent and drops the reference the child held on its former\nparent.  hook_path_rename() is not affected because the rename path\ncalls lock_rename() before the hook, so the source cannot be reparented\nunder it.  hook_path_link() has no such protection: filename_linkat()\nholds a reference on the source dentry but neither locks nor references\nits parent, so a concurrent rename(2) can reparent the source while\nsecurity_path_link() runs, and the former parent can then be removed and\nfreed while the hook walks it.\n\nA process can trigger this after entering a Landlock domain that handles\nat least one filesystem access right.  The process can then race a\nlinkat(2) loop against rename(2) and rmdir(2):\n\n  BUG: KASAN: slab-use-after-free in collect_domain_accesses+0x278/0x290\n  Read of size 4 at addr ffff888160bd53f4 by task llrepro2/549\n   collect_domain_accesses+0x278/0x290\n   current_check_refer_path+0x952/0x1120\n   security_path_link+0x1be/0x320\n   filename_linkat+0x342/0x6d0\n   __x64_sys_linkat+0xfa/0x150\n  Freed by task 562:\n   kmem_cache_free+0x139/0x4c0\n   i_callback+0x4b/0x80\n   rcu_core+0x7dc/0x10a0\n\nTake a reference on the dentry selected as the source parent, using\ndget() for the common-mount-root case and dget_parent() otherwise.\nRelease it after the hierarchy walk and synchronous audit logging.\n\n[mic: Clarify the caller, reachability, and reference handling]"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "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"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The trigger is a local linkat(2) syscall: filename_linkat() -\u003e security_path_link() -\u003e hook_path_link() -\u003e current_check_refer_path(), raced against local rename(2)/rmdir(2). No remote protocol supplies any of the input.\nAC:L - The attacker runs every side of the race: a linkat() loop on their own file, plus rename() to reparent the source and rmdir() to free the old parent, all in directories they create (e.g. /tmp). No condition outside the attacker\u0027s control is needed; the window can be retried at will.\nPR:L - An ordinary unprivileged user can enter a Landlock domain that handles any FS right (landlock_create_ruleset + landlock_restrict_self after PR_SET_NO_NEW_PRIVS, no capability needed); that makes landlock_get_applicable_subject() non-NULL and reaches the unpinned d_parent read.\nUI:N - The attacker\u0027s own syscalls on files and directories they own trigger the bug; no other user or administrator has to do anything.\nS:U - The corruption happens in kernel memory under the same kernel authority; exploiting it is standard local privilege escalation, not a crossing into a separate authority such as a hypervisor.\nC:H - collect_domain_accesses() dereferences the freed old_parent dentry and follows its d_parent/d_inode pointers into the Landlock inode blob via find_rule(). If the attacker reallocates the freed slab, they control pointers that the kernel then follows and reads.\nI:H - collect_domain_accesses() calls dget() and later dput() on the freed dentry. That writes the lockref inside the freed or reallocated object and can run dentry teardown on it, a write primitive that can lead to a double free or control-flow hijack.\nA:H - The KASAN report in the commit shows a slab use-after-free in collect_domain_accesses(). On production kernels the refcount changes on freed memory or the stale pointer walk can oops or panic the kernel."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:53:22.513Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/48fc1c74052c956c59d5b16b5e18e0dd36b76aa2"
        },
        {
          "url": "https://git.kernel.org/stable/c/4c37992b9668c4f37aae41dd95c369f7b6009915"
        },
        {
          "url": "https://git.kernel.org/stable/c/379efd2ce8b26fd35feb13ccc2f671ff105a5052"
        },
        {
          "url": "https://git.kernel.org/stable/c/ba29c46ccfe3ebadfb8aa18149186c49f84b14f8"
        },
        {
          "url": "https://git.kernel.org/stable/c/2c6dc792538260a8087ac5b22c31b3b8e47c85d6"
        }
      ],
      "title": "landlock: Fix use-after-free of the source\u0027s parent directory",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97594",
    "datePublished": "2026-09-25T10:22:10.548Z",
    "dateReserved": "2026-09-24T16:01:01.157Z",
    "dateUpdated": "2026-10-21T12:53:22.513Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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