Security readout for executives and security teams
Plain-English summary
This is a Linux kernel KVM issue on arm64. A userspace virtual machine monitor could ask KVM to pend vCPU events before that vCPU is initialized, causing KVM to use uninitialized state and hit a kernel BUG. The main business concern is host stability for affected ARM virtualization systems.
Executive priority
Treat as a targeted stability risk for ARM virtualization hosts. Patch during the normal kernel maintenance cycle unless untrusted tenants can access KVM interfaces, which raises urgency.
Technical view
KVM arm64 accepted vCPU event ioctls before KVM_ARM_VCPU_INIT. The kernel could then route or inject exceptions using uninitialized vCPU state, including disagreement about 32-bit EL1 handling, producing an illegal mode and BUG in exception_target_el(). The fix rejects those ioctls before initialization.
Likely exposure
Exposure appears limited to Linux arm64 systems using KVM where userspace can interact with KVM vCPU ioctls. The bundle lists affected Linux kernel versions but distribution-specific backports are not identified.
Exploitation context
The source describes a syzkaller-found kernel crash path. The bundle does not cite active exploitation, weaponized public exploits, KEV inclusion, privilege impact, or remote reachability.
Researcher notes
Evidence supports a pre-initialization state handling bug in KVM arm64 vCPU event injection. Impact is demonstrated as kernel BUG/Oops. The bundle lacks CVSS, CWE, exploitability analysis, and distribution-specific fixed version mapping.
Mitigation direction
- Apply vendor kernel updates that include the referenced KVM arm64 fixes.
- Check distribution advisories for backported fixes matching CVE-2025-40102.
- Restrict KVM device access to trusted virtualization components and administrators.
- Prioritize hosts running arm64 KVM workloads or exposing virtualization to tenants.
Validation and detection
- Inventory ARM64 Linux hosts using KVM virtualization.
- Compare running kernel packages against vendor-fixed builds or referenced stable commits.
- Review access controls for userspace components that can create or manage KVM vCPUs.
- Check kernel logs for related KVM arm64 BUG or Oops reports.
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-2025-40102 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/64a04e6320fc5affbadc59dc7024d79f909bfe84CVE reference, Linux
- https://git.kernel.org/stable/c/0aa1b76fe1429629215a7c79820e4b96233ac4a3CVE 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.