Security readout for executives and security teams
Plain-English summary
This is a critical Linux kernel flaw in ksmbd, the in-kernel SMB server. A remote unauthenticated attacker could trigger memory-safety behavior through SMB negotiation handling on vulnerable systems. Business urgency is highest where ksmbd is enabled and reachable from untrusted networks.
Executive priority
Prioritize remediation for any reachable ksmbd servers because the vulnerability is critical, remotely reachable, and requires no authentication. Lower urgency only where ksmbd is absent, disabled, or fully isolated, but still confirm vendor patch status.
Technical view
CVE-2023-38427 affects Linux kernel versions before 6.3.8 in fs/smb/server/smb2pdu.c. The vulnerable deassemble_neg_contexts function has an integer underflow and out-of-bounds read, mapped to CWE-191 and CWE-125. The CVSS 3.1 vector is network, low complexity, no privileges, no user interaction, with high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely on Linux systems running a kernel before 6.3.8 with ksmbd enabled as an SMB server, especially if reachable over internal or external networks. The bundle does not identify precise distributions, appliance versions, or CPEs.
Exploitation context
The CVSS vector indicates remote unauthenticated attack potential. The provided bundle does not show CISA KEV listing or cite active exploitation. Treat exploit status as unconfirmed, not absent.
Researcher notes
The key evidence is the upstream Linux commit and 6.3.8 changelog. The affected product data in the bundle is incomplete, so do not over-broaden to all SMB stacks or Samba. Focus validation on ksmbd presence, kernel lineage, and vendor backports.
Mitigation direction
- Upgrade to Linux kernel 6.3.8 or a vendor-backported fixed kernel.
- Check Linux distribution and appliance vendor advisories for exact fixed packages.
- Restrict ksmbd SMB exposure to trusted networks while patching.
- Disable ksmbd where it is not operationally required.
- Review NetApp guidance if NetApp-managed platforms are in scope.
Validation and detection
- Inventory Linux kernel versions and identify systems below 6.3.8.
- Confirm whether ksmbd is enabled or exposed as an SMB server.
- Verify vendor package changelogs include the referenced kernel fix.
- Map SMB service exposure from internet, partner, and internal networks.
- Check vulnerability scanner results against vendor backport status.
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-125: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-191: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2023-38427 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
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/fs/smb/server?id=f1a411873c85b642f13b01f21b534c2bab81fc1bCVE reference
- https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.3.8CVE reference
- https://security.netapp.com/advisory/ntap-20230824-0011/CVE reference
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.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Integer Underflow (Wrap or Wraparound)
Integer Underflow (Wrap or Wraparound) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.