Vulnerability-Lookup

GHSA-HXMM-JMJ9-253J

Vulnerability from github – Published: 2026-06-25 09:31 – Updated: 2026-06-25 09:31

Details

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

ksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers

smb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo->conn into a local with neither READ_ONCE() nor a NULL check. Both run from oplock_break() after opinfo_get_list() has dropped ci->m_lock, so a concurrent SMB2 LOGOFF (session_fd_check()) can set op->conn = NULL under ci->m_lock within that window. ksmbd_conn_r_count_inc(conn) then writes through NULL at offset 0xc4 -- a remotely triggerable oops.

Guard both reads the way compare_guid_key() already does: read opinfo->conn with READ_ONCE() and return early if it is NULL, before allocating the work struct so nothing leaks. A NULL conn means the client is gone and the break is moot, so return 0; oplock_break() treats that as success and runs the normal teardown.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-53271"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-25T09:16:45Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix NULL-deref of opinfo-\u003econn in oplock/lease break notifiers\n\nsmb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo-\u003econn\ninto a local with neither READ_ONCE() nor a NULL check.  Both run from\noplock_break() after opinfo_get_list() has dropped ci-\u003em_lock, so a\nconcurrent SMB2 LOGOFF (session_fd_check()) can set op-\u003econn = NULL\nunder ci-\u003em_lock within that window.  ksmbd_conn_r_count_inc(conn) then\nwrites through NULL at offset 0xc4 -- a remotely triggerable oops.\n\nGuard both reads the way compare_guid_key() already does: read\nopinfo-\u003econn with READ_ONCE() and return early if it is NULL, before\nallocating the work struct so nothing leaks.  A NULL conn means the\nclient is gone and the break is moot, so return 0; oplock_break() treats\nthat as success and runs the normal teardown.",
  "id": "GHSA-hxmm-jmj9-253j",
  "modified": "2026-06-25T09:31:23Z",
  "published": "2026-06-25T09:31:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53271"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1ff58dcfcab434ebb51649da33774fbb8e1f7b67"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/75e33deda658c1ab3a9336cbdb1436536f9b3660"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/945a86b21b40fb17183f5b27461baa6f03e2467f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b003086d76968298f22e7cf62239833b5a3a06b1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e735dbd489e3ea02be78dba991056fe1138be51e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-53271 (GCVE-0-2026-53271)

Vulnerability from cvelistv5 – Published: 2026-06-25 08:39 – Updated: 2026-06-25 08:39

Title

ksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers smb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo->conn into a local with neither READ_ONCE() nor a NULL check. Both run from oplock_break() after opinfo_get_list() has dropped ci->m_lock, so a concurrent SMB2 LOGOFF (session_fd_check()) can set op->conn = NULL under ci->m_lock within that window. ksmbd_conn_r_count_inc(conn) then writes through NULL at offset 0xc4 -- a remotely triggerable oops. Guard both reads the way compare_guid_key() already does: read opinfo->conn with READ_ONCE() and return early if it is NULL, before allocating the work struct so nothing leaks. A NULL conn means the client is gone and the break is moot, so return 0; oplock_break() treats that as success and runs the normal teardown.

Severity

No CVSS data available.

Assigner

Linux

References

5 references

URL	Tags
https://git.kernel.org/stable/c/945a86b21b40fb171…
https://git.kernel.org/stable/c/1ff58dcfcab434ebb…
https://git.kernel.org/stable/c/e735dbd489e3ea02b…
https://git.kernel.org/stable/c/75e33deda658c1ab3…
https://git.kernel.org/stable/c/b003086d76968298f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 8df4bcdb0a4232192b2445256c39b787d58ef14d , < 945a86b21b40fb17183f5b27461baa6f03e2467f (git) Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < 1ff58dcfcab434ebb51649da33774fbb8e1f7b67 (git) Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < e735dbd489e3ea02be78dba991056fe1138be51e (git) Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < 75e33deda658c1ab3a9336cbdb1436536f9b3660 (git) Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < b003086d76968298f22e7cf62239833b5a3a06b1 (git) Affected: 6.6.32 , < 6.6.143 (semver)
Linux	Linux	Affected: 6.9 Unaffected: 0 , < 6.9 (semver) Unaffected: 6.6.143 , ≤ 6.6.* (semver) Unaffected: 6.12.94 , ≤ 6.12.* (semver) Unaffected: 6.18.36 , ≤ 6.18.* (semver) Unaffected: 7.0.13 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/oplock.c"
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          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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              "versionType": "git"
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            },
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              "versionType": "git"
            },
            {
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              "status": "affected",
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              "status": "affected",
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/oplock.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.94",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.36",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                },
                {
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.9",
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                }
              ],
              "negate": false,
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix NULL-deref of opinfo-\u003econn in oplock/lease break notifiers\n\nsmb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo-\u003econn\ninto a local with neither READ_ONCE() nor a NULL check.  Both run from\noplock_break() after opinfo_get_list() has dropped ci-\u003em_lock, so a\nconcurrent SMB2 LOGOFF (session_fd_check()) can set op-\u003econn = NULL\nunder ci-\u003em_lock within that window.  ksmbd_conn_r_count_inc(conn) then\nwrites through NULL at offset 0xc4 -- a remotely triggerable oops.\n\nGuard both reads the way compare_guid_key() already does: read\nopinfo-\u003econn with READ_ONCE() and return early if it is NULL, before\nallocating the work struct so nothing leaks.  A NULL conn means the\nclient is gone and the break is moot, so return 0; oplock_break() treats\nthat as success and runs the normal teardown."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-25T08:39:56.489Z",
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        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/e735dbd489e3ea02be78dba991056fe1138be51e"
        },
        {
          "url": "https://git.kernel.org/stable/c/75e33deda658c1ab3a9336cbdb1436536f9b3660"
        },
        {
          "url": "https://git.kernel.org/stable/c/b003086d76968298f22e7cf62239833b5a3a06b1"
        }
      ],
      "title": "ksmbd: fix NULL-deref of opinfo-\u003econn in oplock/lease break notifiers",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-53271",
    "datePublished": "2026-06-25T08:39:56.489Z",
    "dateReserved": "2026-06-09T07:44:35.395Z",
    "dateUpdated": "2026-06-25T08:39:56.489Z",
    "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.

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GHSA-HXMM-JMJ9-253J

CVE-2026-53271 (GCVE-0-2026-53271)

Tags

Sightings

Nomenclature