Security readout for executives and security teams
Plain-English summary
This is a Linux kernel clock-driver bug. A missing divider offset can make a calculated clock rate wrong or zero, potentially destabilizing systems that rely on that driver path. The sources do not provide CVSS, confirmed impact scope, or exploit evidence.
Executive priority
Treat as a targeted kernel maintenance issue until more impact evidence appears. Prioritize embedded or hardware-specific Linux fleets over general servers unless asset data shows the affected driver path is present.
Technical view
The issue is in clk/sunxi-ng MP dual-divider clock rate readback. The recalc_rate path omitted the P divider offset, creating bogus rate calculations and possible divide-by-zero behavior. Kernel stable commits correct the calculation by incorporating the P divider offset.
Likely exposure
Exposure appears limited to Linux systems running affected kernel versions and using the sunxi-ng MP dual-divider clock code path. The bundle lists Linux as affected, including 6.15, 6.16.9, and 6.17 entries, but version semantics are incomplete.
Exploitation context
The bundle marks KEV as false and provides no public exploitation evidence. The available description supports a reliability or availability concern inside kernel clock handling, not a confirmed remotely exploitable vulnerability.
Researcher notes
Key uncertainty is impact breadth. The CVE text identifies an incorrect rate readback and possible divide-by-zero, but does not provide CVSS, CWE, exploitability analysis, affected hardware list, or distro-level fixed versions.
Mitigation direction
- Review Linux kernel stable guidance for the referenced commits.
- Update affected kernels to a version containing the stable fixes.
- Prioritize systems using the sunxi-ng clock driver path.
- Monitor vendor distributions for backported kernel advisories.
Validation and detection
- Inventory Linux kernel versions across relevant assets.
- Check whether deployed kernels include the two referenced stable commits.
- Identify systems using sunxi-ng MP clock support.
- Track distribution advisories for CVE-2025-39954 status.
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-2025-39954 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/40108f69c372af3aea73e7829d6849a44638d662CVE reference, Linux
- https://git.kernel.org/stable/c/25fbbaf515acd13399589bd5ee6de5f35740cef2CVE 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.