Cloudanix VulnDB

CVE-2026-98450

None

CVSS

—

EPSS

0.2%

Published

Oct 18, 2026

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A bug in how Linux handles certain network file operations with Windows servers can leave files open on the server when network requests are interrupted, potentially wasting server resources until fixed by a kernel update.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Denial Of Service
Component
OS kernel
Class
Other
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Incomplete error handling in compound_send_recv() for SMB CREATE MIDs allows a remote file handle to remain open on the server when a later MID in the compound fails or is interrupted, because handle_cancelled_mid() is not invoked and no FID is returned to the caller.

Why it matters to the business

Linux SMB clients may leak remote file handles, leading to resource exhaustion on file servers, unexpected open file counts, and potential operational disruptions during interrupted compound operations such as unlinks or creates.

How an attack unfolds

An attacker triggers a compound SMB request containing a CREATE followed by another operation; by interrupting the wait or causing a later MID synchronization failure, the earlier CREATE succeeds on the server but the client releases the MID without closing the handle, leaving the remote resource open.

How to fix it

Apply the upstream Linux kernel fix that marks completed earlier CREATE MIDs as cancelled, retains response buffers during synchronization, and queues SMB2_close() when a later failure occurs; update to a kernel version containing this change once released.

How to confirm the fix worked

Confirm the patch is present by inspecting the smb client compound handling code for the new cancellation and close-queuing logic on CREATE MIDs; test compound operations with injected wait interruptions to verify no leaked handles remain.

Typical attack path

  1. Initiate a compound SMB request that includes a CREATE MID followed by additional commands
  2. Force an interruption or synchronization failure on a later MID in the compound
  3. Allow the client to release the earlier CREATE MID without invoking cancellation logic
  4. Observe the resulting leaked remote handle on the server

How to detect it

Examine kernel logs and SMB client traces for compound MID synchronization errors or aborted waits involving CREATE operations; look for unexpected increases in remote open counts reported by the server without corresponding client-side FIDs.

What your security team should do

  • Monitor for availability of the kernel patch and schedule deployment within standard update windows given low EPSS and no known exploitation
  • Review SMB client workloads that rely on compound requests for create and unlink patterns
  • Track open file handle counts on SMB servers as a general health metric

The record

In the Linux kernel, the following vulnerability has been resolved: smb: client: close completed creates on compound wait errors compound_send_recv() waits for responses in order. If a later wait is interrupted, or if a later MID fails during response synchronization, an earlier CREATE may already have opened a remote handle. The earlier mid is then released without invoking handle_cancelled_mid(), leaving the remote handle open because no FID was copied to the caller. Mark completed earlier mids as cancelled when a compound wait or MID synchronization aborts. Keep their response buffers attached while the MIDs are synchronized, and transfer them only after synchronization of the processed responses, so the release path can inspect successful CREATE responses and queue SMB2_close() after a later failure. Account for a remote open only after the close work is allocated and before it is queued, since the caller has not yet updated num_remote_opens. Mark the create+close compound used by smb2_unlink() so it is not closed again. Non-CREATE responses and compounds that already include a close keep their existing behavior.

Affected packages

Ecosystem Package Introduced Fixed