Vulnerability-Lookup

GHSA-H9QG-8GF5-6W98

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33

Details

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

ksmbd: fix use-after-free in same_client_has_lease()

same_client_has_lease() returns an opinfo pointer from ci->m_op_list after dropping ci->m_lock without taking a reference.

smb_grant_oplock() then dereferences that pointer in copy_lease() and when checking breaking_cnt. A concurrent close can remove the old lease from ci->m_op_list and drop the last reference before the caller uses the returned pointer, leading to a use-after-free.

Take a reference when same_client_has_lease() selects an existing lease, drop any previous match while scanning, and release the returned reference in smb_grant_oplock() after copying the lease state.

Severity

8.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72492"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:22:23Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free in same_client_has_lease()\n\nsame_client_has_lease() returns an opinfo pointer from ci-\u003em_op_list\nafter dropping ci-\u003em_lock without taking a reference.\n\nsmb_grant_oplock() then dereferences that pointer in copy_lease() and\nwhen checking breaking_cnt. A concurrent close can remove the old lease\nfrom ci-\u003em_op_list and drop the last reference before the caller uses\nthe returned pointer, leading to a use-after-free.\n\nTake a reference when same_client_has_lease() selects an existing lease,\ndrop any previous match while scanning, and release the returned\nreference in smb_grant_oplock() after copying the lease state.",
  "id": "GHSA-h9qg-8gf5-6w98",
  "modified": "2026-08-17T06:33:33Z",
  "published": "2026-08-15T06:32:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72492"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/09634cd055d9bd8dd167995ea52bcd8028dd5dac"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0ff82a9cf9312678d8bc4edeef0b6e82659ac12a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/35d3d6ff2bc1e7aaecb15d5377ebbd6227acae0d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/65b655f65c3ca1ab5d598d3832bb0ff531725858"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/79c7c59bb519db6f5a2a151965e825ec725614cc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7c3264d273d524aa6adcce23c01087271f13586f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aaa3bb2bbf2ccbfea9e4e0b9dabf3afc60b50cd0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-72492 (GCVE-0-2026-72492)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:57 – Updated: 2026-08-17 05:44

Title

ksmbd: fix use-after-free in same_client_has_lease()

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in same_client_has_lease() same_client_has_lease() returns an opinfo pointer from ci->m_op_list after dropping ci->m_lock without taking a reference. smb_grant_oplock() then dereferences that pointer in copy_lease() and when checking breaking_cnt. A concurrent close can remove the old lease from ci->m_op_list and drop the last reference before the caller uses the returned pointer, leading to a use-after-free. Take a reference when same_client_has_lease() selects an existing lease, drop any previous match while scanning, and release the returned reference in smb_grant_oplock() after copying the lease state.

Severity

8.8 (High)


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

Assigner

Linux mitre root

References

7 references

URL	Tags
https://git.kernel.org/stable/c/aaa3bb2bbf2ccbfea…
https://git.kernel.org/stable/c/09634cd055d9bd8dd…
https://git.kernel.org/stable/c/7c3264d273d524aa6…
https://git.kernel.org/stable/c/79c7c59bb519db6f5…
https://git.kernel.org/stable/c/35d3d6ff2bc1e7aae…
https://git.kernel.org/stable/c/0ff82a9cf9312678d…
https://git.kernel.org/stable/c/65b655f65c3ca1ab5…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < aaa3bb2bbf2ccbfea9e4e0b9dabf3afc60b50cd0 (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 09634cd055d9bd8dd167995ea52bcd8028dd5dac (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 7c3264d273d524aa6adcce23c01087271f13586f (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 79c7c59bb519db6f5a2a151965e825ec725614cc (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 35d3d6ff2bc1e7aaecb15d5377ebbd6227acae0d (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 0ff82a9cf9312678d8bc4edeef0b6e82659ac12a (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 65b655f65c3ca1ab5d598d3832bb0ff531725858 (git)
Linux	Linux	Affected: 5.15 Unaffected: 0 , < 5.15 (semver) Unaffected: 5.15.212 , ≤ 5.15.* (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/oplock.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "status": "affected",
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              "versionType": "git"
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              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
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              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
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          "vendor": "Linux",
          "versions": [
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              "version": "5.15"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.212",
                  "versionStartIncluding": "5.15",
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                },
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                }
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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\nksmbd: fix use-after-free in same_client_has_lease()\n\nsame_client_has_lease() returns an opinfo pointer from ci-\u003em_op_list\nafter dropping ci-\u003em_lock without taking a reference.\n\nsmb_grant_oplock() then dereferences that pointer in copy_lease() and\nwhen checking breaking_cnt. A concurrent close can remove the old lease\nfrom ci-\u003em_op_list and drop the last reference before the caller uses\nthe returned pointer, leading to a use-after-free.\n\nTake a reference when same_client_has_lease() selects an existing lease,\ndrop any previous match while scanning, and release the returned\nreference in smb_grant_oplock() after copying the lease state."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - ksmbd is the in-kernel SMB server on TCP/445; the UAF is reached when a remote client sends SMB2_CREATE with a lease context, handled via ksmbd_conn_handler_loop() through smb2_open() and smb_grant_oplock() into same_client_has_lease().\nAC:L - The attacker controls both sides of the race by holding a leased open on one SMB connection while concurrently issuing SMB2_CREATE (lease upgrade) and SMB2_CLOSE on another connection or channel; no victim-dependent timing or memory layout is required.\nPR:L - Exploitation requires a valid SMB2 session, tree connect, and share permission to open/close the target file with SMB3 leasing enabled; smb2_check_user_session() rejects SMB2_CREATE without SMB2_SESSION_VALID, so this is not reachable on pre-authentication negotiate/echo paths.\nUI:N - No victim interaction is required; the attacker drives all SMB2_CREATE and SMB2_CLOSE operations on their own client connection(s) to trigger the concurrent lease lookup and file close.\nS:U - Impact is kernel heap corruption and privilege escalation on the SMB server host within the ksmbd/kernel security authority; it does not cross a VM, container, or IOMMU boundary.\nC:H - Use-after-free of a freed oplock_info/lease object in copy_lease() reads attacker-influenced slab contents (level, lease state, keys, flags, epoch), enabling kernel memory disclosure and arbitrary-read primitive construction.\nI:H - The UAF dereferences freed oplock_info and embedded lease pointers during copy_lease() and breaking_cnt checks, enabling heap grooming and memory corruption exploitable for arbitrary write or control-flow hijack as root.\nA:H - Concurrent close can free the oplock_info before smb_grant_oplock() uses it, causing reliable kernel memory corruption, oops, or panic and repeatable remote denial of service against the server."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:44:53.329Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/aaa3bb2bbf2ccbfea9e4e0b9dabf3afc60b50cd0"
        },
        {
          "url": "https://git.kernel.org/stable/c/09634cd055d9bd8dd167995ea52bcd8028dd5dac"
        },
        {
          "url": "https://git.kernel.org/stable/c/7c3264d273d524aa6adcce23c01087271f13586f"
        },
        {
          "url": "https://git.kernel.org/stable/c/79c7c59bb519db6f5a2a151965e825ec725614cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/35d3d6ff2bc1e7aaecb15d5377ebbd6227acae0d"
        },
        {
          "url": "https://git.kernel.org/stable/c/0ff82a9cf9312678d8bc4edeef0b6e82659ac12a"
        },
        {
          "url": "https://git.kernel.org/stable/c/65b655f65c3ca1ab5d598d3832bb0ff531725858"
        }
      ],
      "title": "ksmbd: fix use-after-free in same_client_has_lease()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72492",
    "datePublished": "2026-08-15T05:57:26.967Z",
    "dateReserved": "2026-08-09T03:40:39.936Z",
    "dateUpdated": "2026-08-17T05:44:53.329Z",
    "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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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GHSA-H9QG-8GF5-6W98

CVE-2026-72492 (GCVE-0-2026-72492)

Tags

Sightings

Nomenclature