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CVE Record

CVE-2022-49004: riscv: Sync efi page table's kernel mappings before switching

In the Linux kernel, the following vulnerability has been resolved: riscv: Sync efi page table's kernel mappings before switching The EFI page table is initially created as a copy of the kernel page table. With VMAP_STACK enabled, kernel stacks are allocated in the vmalloc area: if the stack is allocated in a new PGD (one that was not present at the moment of the efi page table creation or not synced in a previous vmalloc fault), the kernel will take a trap when switching to the efi page table when the vmalloc kernel stack is accessed, resulting in a kernel panic. Fix that by updating the efi kernel mappings before switching to the efi page table.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue affects specific RISC-V systems using EFI page tables. Under certain memory-mapping conditions, the kernel can panic when switching page tables, causing an outage or reboot. Public sources do not provide a CVSS score or evidence of active exploitation.

Executive priority

Treat as a targeted availability risk for RISC-V Linux environments, not a broad enterprise emergency. Prioritize patch validation where RISC-V systems support production, embedded, or availability-sensitive services.

Technical view

The EFI page table begins as a copy of the kernel page table. With VMAP_STACK enabled, stacks may be allocated in vmalloc space after EFI mappings are created. If a needed PGD is missing, switching to the EFI page table can trap and panic. The fix syncs EFI kernel mappings before switching.

Likely exposure

Likely limited to Linux on RISC-V systems using EFI and VMAP_STACK in affected kernel lines identified by the CVE record, including 5.10, 5.15.82, 6.0.12, and 6.1. Non-RISC-V systems are not indicated by the sources.

Exploitation context

The sources describe a kernel panic condition, not a practical attack path. No cited source states active exploitation, public exploit availability, or remote triggerability. CISA KEV is not indicated in the provided data.

Researcher notes

Evidence is concise and kernel-maintainer focused. The CVE record describes the fault and fix but does not include CVSS, CWE, exploit status, or detailed attack prerequisites. Assessment should be confirmed against downstream distribution advisories.

Mitigation direction

  • Check your Linux vendor’s advisory for CVE-2022-49004 and applicable RISC-V kernels.
  • Upgrade to a kernel build containing the referenced stable kernel fix commits.
  • Prioritize RISC-V systems that boot with EFI and run critical workloads.
  • If updates are unavailable, ask the vendor for supported mitigations or backports.

Validation and detection

  • Inventory systems running Linux on RISC-V hardware or virtual platforms.
  • Confirm whether affected kernels use EFI and VMAP_STACK.
  • Compare installed kernel packages against vendor-fixed builds or referenced stable commits.
  • Review crash logs for kernel panics around EFI page table switching.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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.

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CVE-2022-49004 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
3Timeline events
1ADP providers
4Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxb91540d52a08b65eb6a2b09132e1bd54fa82754c, b91540d52a08b65eb6a2b09132e1bd54fa82754c, b91540d52a08b65eb6a2b09132e1bd54fa82754cunaffected
LinuxLinux5.10, 0, 5.15.82, 6.0.12, 6.1affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.