Security readout for executives and security teams
Plain-English summary
CVE-2025-40052 is a Linux kernel SMB client crash bug. Systems using encrypted SMB/CIFS mounts can hit a kernel BUG during heavy parallel reads and writes, potentially disrupting the host. The source bundle does not provide CVSS scoring or evidence of active exploitation.
Executive priority
Treat as a targeted availability risk, not a confirmed breach indicator. Patch affected Linux SMB clients in normal kernel maintenance, faster for file-service clients where outages would affect operations.
Technical view
The SMB client crypto path allocates an AEAD request with kvzalloc(), which can place private crypto context in vmalloc memory. Scatterlist users expect linear memory and may call sg_set_buf(), triggering virt_addr_valid() failure and a kernel BUG under encrypted parallel I/O.
Likely exposure
Exposure is most likely on Linux hosts using the CIFS/SMB client with encrypted SMB mounts, especially under high concurrent read/write workloads. Systems not mounting encrypted SMB shares are less likely to encounter the described trigger.
Exploitation context
The provided sources describe a reliability-triggered kernel BUG from parallel encrypted SMB I/O. KEV is false, and no cited source reports active exploitation or a public weaponized exploit.
Researcher notes
The evidence supports a kernel denial-of-service condition through an internal BUG, but not privilege escalation, data theft, or remote server compromise. Affected version data in the bundle is sparse, so rely on distro backport status.
Mitigation direction
- Apply Linux kernel or distribution updates containing the referenced stable fixes.
- Prioritize systems with encrypted CIFS/SMB mounts and high parallel file I/O.
- Check vendor advisories for exact affected package versions and backports.
- If patching is delayed, reduce high-concurrency encrypted SMB workloads where operationally feasible.
Validation and detection
- Inventory Linux systems mounting CIFS/SMB shares with encryption enabled.
- Map running kernel versions to vendor advisories or referenced stable commits.
- Review logs for cifs, crypt_message, crypto_gcm, scatterlist, or kernel BUG traces.
- Regression-test encrypted SMB read/write workloads after kernel updates.
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-2025-40052 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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.
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/ba905a567105dde21cdb8e6d3a87110fa434b393CVE reference, Linux
- https://git.kernel.org/stable/c/7a8a8c15468f0c99685e9964451feffd1a3cc859CVE reference, Linux
- https://git.kernel.org/stable/c/4a61b68abd2788db0364c9a0b6a39f1699fea440CVE reference, Linux
- https://git.kernel.org/stable/c/998a67b954680f26f3734040aeeed08642d49721CVE 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.