Security readout for executives and security teams
Plain-English summary
A race condition in the Linux kernel’s ksmbd SMB server can access memory after it has been freed. A low-privileged remote user may be able to trigger the flaw without user interaction, potentially affecting confidentiality, integrity, and availability. Systems are exposed only if they use the vulnerable ksmbd functionality.
Executive priority
Treat as a high-priority patching and exposure-review item for ksmbd-based file servers, especially those reachable from untrusted networks. Accelerate remediation where low-privileged SMB accounts exist. General Linux systems without ksmbd exposure have substantially lower urgency for this specific issue.
Technical view
CVE-2025-37926 is a use-after-free caused by concurrent ksmbd_session_rpc_open() and __session_rpc_close() operations. The kernel fix adds an rpc_lock to protect session RPC state. CVSS 3.1 rates it 8.8: network-accessible, low complexity, low privileges required, no user interaction, with potentially high security impact.
Likely exposure
Prioritize Linux systems running ksmbd and offering SMB to untrusted or broadly accessible networks. The supplied affected-version data is ambiguous and should not be treated as a reliable fixed-version boundary. Systems not using ksmbd are unlikely to expose this specific vulnerable path.
Exploitation context
The bundle does not identify CVE-2025-37926 as a CISA KEV entry and provides no evidence of active exploitation or a public exploit. Its network vector, low complexity, and low privilege requirement nevertheless make reachable ksmbd servers important to assess promptly.
Researcher notes
The source bundle establishes the race, use-after-free, locking fix, and five stable-kernel commits. It does not establish exploitation mechanics, affected distributions, or dependable vulnerable-to-fixed version ranges. Validate backports by code change or vendor advisory rather than version comparison alone.
Mitigation direction
- Apply a vendor-supported kernel update containing the referenced ksmbd fix or an equivalent backport.
- Restrict SMB access to trusted networks and authorized users while updates are pending.
- Disable ksmbd where SMB service is unnecessary, following operating-system vendor guidance.
- Reboot into the updated kernel and confirm the previous kernel is no longer active.
Validation and detection
- Inventory systems for loaded, enabled, or configured ksmbd functionality.
- Identify the running kernel build and compare it with distribution security guidance.
- Verify the installed kernel contains the referenced rpc_lock fix or an equivalent backport.
- Confirm SMB is not exposed beyond intended network boundaries.
- After updating, verify services operate normally and the corrected kernel is running.
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.
CVE-2025-37926 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
- 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/a4348710a7267705b75692dc1a000920481d1d92CVE reference, Linux
- https://git.kernel.org/stable/c/1067361a1cc6ad9cdf7acfc47f90012b72ad1502CVE reference, Linux
- https://git.kernel.org/stable/c/8fb3b6c85b7e3127161623586b62abcc366caa20CVE reference, Linux
- https://git.kernel.org/stable/c/6323fec65fe54b365961fed260dd579191e46121CVE reference, Linux
- https://git.kernel.org/stable/c/a1f46c99d9ea411f9bf30025b912d881d36fc709CVE 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.