Security readout for executives and security teams
Plain-English summary
A synchronization flaw in Linux’s ksmbd SMB server can cause memory to be used after it has been freed during multi-channel sessions. A network attacker with low privileges may be able to compromise confidentiality, integrity, or availability. Risk is concentrated on systems actively running and exposing ksmbd.
Executive priority
Treat this as a high-priority infrastructure issue where ksmbd is active and network-accessible. Promptly inventory SMB servers and patch confirmed exposure. Systems without ksmbd can be deprioritized after verification. There is no source-backed evidence of active exploitation, but the potential impact and favorable CVSS attack conditions justify accelerated remediation.
Technical view
The ksmbd channel xarray lacked synchronization between channel lookup and deletion, creating a use-after-free race in multi-channel sessions. The documented correction adds a per-session read-write semaphore and protects xa_load, xa_store, and xa_erase operations. CVSS 3.1 scores the issue 8.8 with network reachability, low complexity, and low privileges required.
Likely exposure
Exposure requires Linux systems using the in-kernel ksmbd server, particularly multi-channel functionality, with SMB reachable by a low-privileged attacker. Systems not running ksmbd are unlikely to expose this path. The supplied version information is irregular, so distribution package status and backported fixes require verification.
Exploitation context
The CVSS assessment indicates substantial remote impact with low attack complexity, low privileges, and no user interaction. The CVE is not listed as KEV, and the supplied sources provide no evidence of active exploitation or a publicly available exploit. Practical exploit reliability is not established by this bundle.
Researcher notes
The core condition is a race between lookup_chann_list() and ksmbd_chann_del over an unsynchronized ksmbd_chann_list xarray. The correction introduces chann_lock in ksmbd_session and serializes relevant xarray accesses. The bundle does not establish exploitability details, affected distribution packages, or whether every listed upstream version maps directly to a vulnerable release.
Mitigation direction
- Apply a supported kernel update containing the referenced synchronization correction or an equivalent distribution backport.
- Check the Linux distribution’s advisory for exact affected and fixed package versions before deployment.
- If updating is delayed, consult vendor guidance for supported temporary controls; the supplied sources name none.
- Prioritize remediation on ksmbd servers reachable from untrusted or broadly accessible networks.
Validation and detection
- Identify systems where ksmbd is installed, loaded, enabled, or providing SMB service.
- Determine whether multi-channel SMB sessions are enabled or used on those systems.
- Record exact kernel and distribution package versions, including vendor backport information.
- Confirm the deployed kernel contains a referenced correction or an equivalent distribution patch.
- Reassess SMB network reachability and authentication boundaries after remediation.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CVE-2026-23226 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9LinuxVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/4c2ca31608521895dd742a43beca4b4d29762345CVE reference, Linux
- https://git.kernel.org/stable/c/e4a8a96a93d08570e0405cfd989a8a07e5b6ff33CVE reference, Linux
- https://git.kernel.org/stable/c/36ef605c0395b94b826a8c8d6f2697071173de6eCVE reference, Linux
- https://git.kernel.org/stable/c/4f3a06cc57976cafa8c6f716646be6c79a99e485CVE reference, Linux
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.