Security readout for executives and security teams
Plain-English summary
CVE-2023-32256 is a Linux kernel ksmbd flaw that can cause memory corruption during certain SMB multichannel sessions. The main business risk is service disruption on systems using the in-kernel SMB server. Available sources do not show active exploitation or Red Hat impact.
Executive priority
Treat this as high priority where ksmbd is deployed or externally reachable. It is less urgent for standard Red Hat fleets marked unaffected or systems not using ksmbd. Prioritize inventory first, then patch or disable the service based on actual exposure.
Technical view
The flaw is a race condition between SMB2 close and logoff handling in ksmbd multichannel connections, leading to use-after-free. The CVSS 3.1 score is 7.5 with network reachability, no privileges, no user interaction, high attack complexity, low confidentiality impact, and high availability impact.
Likely exposure
Exposure appears limited to Linux systems running ksmbd on affected kernel lines listed as 6.0.0, 6.1.0, 6.2.0, and 6.3.0. Red Hat Enterprise Linux 6, 7, 8, 9, and 10 entries are listed as unaffected in the provided source bundle.
Exploitation context
The provided data says this CVE is not in KEV, and no cited source states active exploitation. ZDI published an advisory, and an upstream Linux commit is referenced. Attack feasibility is constrained by high attack complexity and the need for ksmbd multichannel race timing.
Researcher notes
Evidence supports a ksmbd multichannel use-after-free race, not a broad Linux SMB issue across all implementations. The source bundle gives affected kernel lines and an upstream commit reference, but does not provide exploit details, confirmed exploitation, or complete distribution-specific fixed versions.
Mitigation direction
- Identify systems using the Linux ksmbd in-kernel SMB server.
- Check distribution or vendor advisories for kernels containing the referenced upstream fix.
- Apply supported kernel updates where your vendor marks this CVE fixed.
- Disable ksmbd where it is not required for business operations.
- Restrict SMB exposure to trusted networks where feasible.
Validation and detection
- Inventory kernel versions and confirm whether ksmbd is enabled.
- Check whether exposed SMB services are kernel ksmbd rather than another SMB implementation.
- Verify Red Hat systems against Red Hat’s unaffected product status.
- Confirm patched systems run a vendor kernel containing the upstream correction.
- Review monitoring for ksmbd crashes or abnormal SMB session failures.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-421: Exact CWE lookup
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Open ATT&CK lookupCVE-2023-32256 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/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.
SSVC decision data
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:H/PR:N/UI:N/S:C/C:L/I:N/A:H2.24.7redhatVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/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.
- Source timelineredhat
Made public.
- Source timelineredhat
Reported to Red Hat.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://access.redhat.com/security/cve/CVE-2023-32256CVE reference, redhat · vdb-entry, x_refsource_REDHAT
- RHBZ#2385885CVE reference, redhat · issue-tracking, x_refsource_REDHAT
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=abcc506a9a71976a8b4c9bf3ee6efd13229c1e19CVE reference, redhat
- https://www.zerodayinitiative.com/advisories/ZDI-23-704/CVE reference, redhat
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.