Vulnerability-Lookup

GHSA-223F-GCH2-XVQ3

Vulnerability from github – Published: 2026-04-22 15:31 – Updated: 2026-04-22 15:31

Details

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

ksmbd: do not expire session on binding failure

When a multichannel session binding request fails (e.g. wrong password), the error path unconditionally sets sess->state = SMB2_SESSION_EXPIRED. However, during binding, sess points to the target session looked up via ksmbd_session_lookup_slowpath() -- which belongs to another connection's user. This allows a remote attacker to invalidate any active session by simply sending a binding request with a wrong password (DoS).

Fix this by skipping session expiration when the failed request was a binding attempt, since the session does not belong to the current connection. The reference taken by ksmbd_session_lookup_slowpath() is still correctly released via ksmbd_user_session_put().

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{
  "affected": [],
  "aliases": [
    "CVE-2026-31476"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-22T14:16:44Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: do not expire session on binding failure\n\nWhen a multichannel session binding request fails (e.g. wrong password),\nthe error path unconditionally sets sess-\u003estate = SMB2_SESSION_EXPIRED.\nHowever, during binding, sess points to the target session looked up via\nksmbd_session_lookup_slowpath() -- which belongs to another connection\u0027s\nuser. This allows a remote attacker to invalidate any active session by\nsimply sending a binding request with a wrong password (DoS).\n\nFix this by skipping session expiration when the failed request was\na binding attempt, since the session does not belong to the current\nconnection. The reference taken by ksmbd_session_lookup_slowpath() is\nstill correctly released via ksmbd_user_session_put().",
  "id": "GHSA-223f-gch2-xvq3",
  "modified": "2026-04-22T15:31:42Z",
  "published": "2026-04-22T15:31:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31476"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1d1888b4a7aec518b707f6eca0bf08992c0e8da3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6fafc4c4238e538969f1375f9ecdc6587c53f1cc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9bbb19d21ded7d78645506f20d8c44895e3d0fb9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a897064a457056acb976e20e3007cdf553de340f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e0e5edc81b241c70355217de7e120c97c3429deb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f5300690c23c5ac860499bb37dbc09cf43fd62e6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-31476 (GCVE-0-2026-31476)

Vulnerability from cvelistv5 – Published: 2026-04-22 13:54 – Updated: 2026-04-23 15:18

Title

ksmbd: do not expire session on binding failure

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: do not expire session on binding failure When a multichannel session binding request fails (e.g. wrong password), the error path unconditionally sets sess->state = SMB2_SESSION_EXPIRED. However, during binding, sess points to the target session looked up via ksmbd_session_lookup_slowpath() -- which belongs to another connection's user. This allows a remote attacker to invalidate any active session by simply sending a binding request with a wrong password (DoS). Fix this by skipping session expiration when the failed request was a binding attempt, since the session does not belong to the current connection. The reference taken by ksmbd_session_lookup_slowpath() is still correctly released via ksmbd_user_session_put().

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/f5300690c23c5ac86…
	https://git.kernel.org/stable/c/6fafc4c4238e53896…
	https://git.kernel.org/stable/c/1d1888b4a7aec518b…
	https://git.kernel.org/stable/c/a897064a457056acb…
	https://git.kernel.org/stable/c/e0e5edc81b241c703…
	https://git.kernel.org/stable/c/9bbb19d21ded7d786…

Impacted products

Vendor

Product

Version

Linux

Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < f5300690c23c5ac860499bb37dbc09cf43fd62e6 (git)
Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < 6fafc4c4238e538969f1375f9ecdc6587c53f1cc (git)
Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < 1d1888b4a7aec518b707f6eca0bf08992c0e8da3 (git)
Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < a897064a457056acb976e20e3007cdf553de340f (git)
Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < e0e5edc81b241c70355217de7e120c97c3429deb (git)
Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < 9bbb19d21ded7d78645506f20d8c44895e3d0fb9 (git)

Linux

Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 6.1.168 , ≤ 6.1.* (semver)
Unaffected: 6.6.131 , ≤ 6.6.* (semver)
Unaffected: 6.12.80 , ≤ 6.12.* (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "f5300690c23c5ac860499bb37dbc09cf43fd62e6",
              "status": "affected",
              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
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              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
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            },
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              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
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            },
            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "e0e5edc81b241c70355217de7e120c97c3429deb",
              "status": "affected",
              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
              "versionType": "git"
            },
            {
              "lessThan": "9bbb19d21ded7d78645506f20d8c44895e3d0fb9",
              "status": "affected",
              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.168",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.131",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.80",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.21",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.168",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
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                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
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                  "vulnerable": true
                },
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                  "vulnerable": true
                },
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                },
                {
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                }
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              "operator": "OR"
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: do not expire session on binding failure\n\nWhen a multichannel session binding request fails (e.g. wrong password),\nthe error path unconditionally sets sess-\u003estate = SMB2_SESSION_EXPIRED.\nHowever, during binding, sess points to the target session looked up via\nksmbd_session_lookup_slowpath() -- which belongs to another connection\u0027s\nuser. This allows a remote attacker to invalidate any active session by\nsimply sending a binding request with a wrong password (DoS).\n\nFix this by skipping session expiration when the failed request was\na binding attempt, since the session does not belong to the current\nconnection. The reference taken by ksmbd_session_lookup_slowpath() is\nstill correctly released via ksmbd_user_session_put()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-23T15:18:35.031Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/f5300690c23c5ac860499bb37dbc09cf43fd62e6"
        },
        {
          "url": "https://git.kernel.org/stable/c/6fafc4c4238e538969f1375f9ecdc6587c53f1cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/1d1888b4a7aec518b707f6eca0bf08992c0e8da3"
        },
        {
          "url": "https://git.kernel.org/stable/c/a897064a457056acb976e20e3007cdf553de340f"
        },
        {
          "url": "https://git.kernel.org/stable/c/e0e5edc81b241c70355217de7e120c97c3429deb"
        },
        {
          "url": "https://git.kernel.org/stable/c/9bbb19d21ded7d78645506f20d8c44895e3d0fb9"
        }
      ],
      "title": "ksmbd: do not expire session on binding failure",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31476",
    "datePublished": "2026-04-22T13:54:04.779Z",
    "dateReserved": "2026-03-09T15:48:24.098Z",
    "dateUpdated": "2026-04-23T15:18:35.031Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

GHSA-223F-GCH2-XVQ3

CVE-2026-31476 (GCVE-0-2026-31476)

Tags

Sightings

Nomenclature