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ksmbd: follow SMB2 session expiration semantics

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ksmbd: follow SMB2 session expiration semantics ksmbd_session_register() destroys valid sessions after ten seconds of inactivity whenever a client starts another SessionSetup exchange. This confuses Session.IdleTime with Session.ExpirationTime. Windows can create additional authenticated sessions on an existing connection, so deleting the older session invalidates its tree connects and makes mapped drives fail with STATUS_NETWORK_NAME_DELETED. The session expiration rules require the server to change a valid session to expired only after its credential expiration time passes. A valid or expired session otherwise keeps its connection from being scavenged. Connections that have not negotiated a dialect, have no sessions, or have only InProgress sessions are disconnected after an implementation-specific timeout. Use the Windows-compatible 45 second value and run the expiration check periodically for both TCP and SMB Direct. Keep zero as an infinite credential expiration time, and count each Valid-to-Expired transition. Set expired sessions to InProgress when they reauthenticate. If authentication fails, remove the session from the global and per-connection tables immediately, including SMB3 multichannel connections. Retain protection against abandoned SessionId-zero exchanges by allowing only one InProgress authentication per connection. Additional exchanges fail with STATUS_INSUFFICIENT_RESOURCES, and stale InP

Announced Source revision 1
Original source ↗

CVE-2026-98420

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98420

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "ea174a91893956450510945a0c5d1a10b5323656",
        "lessThan": "c99ea7855124ca1428a1e59c2b4590aaef34eacf",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ea174a91893956450510945a0c5d1a10b5323656",
        "lessThan": "d7fd1f98607f2cd358e583f9548bdf0173090a86",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a6a9601ba995d0fec635324cb9fd8d14f9bea14e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1fc8a2b14ef5223f8e0b95faba2ee0a6e4d0f99d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "750a2d772e9d9ff377fd32e3b6797bf2cd847a7a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6775ee7ef4b37c521aa4cf3730f54554c4875542",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "5.15.145",
        "lessThan": "5.16",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.1.29",
        "lessThan": "6.2",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.2.16",
        "lessThan": "6.3",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.3.2",
        "lessThan": "6.4",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "fs/smb/server/connection.c",
      "fs/smb/server/connection.h",
      "fs/smb/server/mgmt/user_session.c",
      "fs/smb/server/mgmt/user_session.h",
      "fs/smb/server/proc.c",
      "fs/smb/server/server.c",
      "fs/smb/server/smb2pdu.c",
      "fs/smb/server/smb2pdu.h",
      "fs/smb/server/stats.h"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.4"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.4",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "7.2.8",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/smb/server/connection.c",
      "fs/smb/server/connection.h",
      "fs/smb/server/mgmt/user_session.c",
      "fs/smb/server/mgmt/user_session.h",
      "fs/smb/server/proc.c",
      "fs/smb/server/server.c",
      "fs/smb/server/smb2pdu.c",
      "fs/smb/server/smb2pdu.h",
      "fs/smb/server/stats.h"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98420

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#38484 · Revision 1
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Publisher date
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