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Response snapshot Nov 6, 2026, 17:11 UTC

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VulnerabilityCVE-2026-45851

Linux kernel: efi: Fix reservation of unaccepted memory table

In the Linux kernel, the following vulnerability has been resolved: efi: Fix reservation of unaccepted memory table The reserve_unaccepted() function incorrectly calculates the size of the memblock reservation for the unaccepted memory table.

At a glance

Exploited
Not known
Severity
7.1 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-45851 (opens a new tab)

What happened

In the Linux kernel, the following vulnerability has been resolved:

efi: Fix reservation of unaccepted memory table

The reserve_unaccepted() function incorrectly calculates the size of the memblock reservation for the unaccepted memory table. It aligns the size of the table, but fails to account for cases where the table's starting physical address (efi.unaccepted) is not page-aligned.

If the table starts at an offset within a page and its end crosses into a subsequent page that the aligned size does not cover, the end of the table will not be reserved. This can lead to the table being overwritten or inaccessible, causing a kernel panic in accept_memory().

Continue reading

This issue was observed when starting Intel TDX VMs with specific memory sizes (e.g., > 64GB).

Fix this by calculating the end address first (including the unaligned start) and then aligning it up, ensuring the entire range is covered by the reservation.

Scores and how they were measured

CVSS base severity

7.1

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-45851 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 6). Linux kernel: efi: Fix reservation of unaccepted memory table (CVE-2026-45851). https://kevwire.com/record/CVE-2026-45851

MLA

"Linux kernel: efi: Fix reservation of unaccepted memory table (CVE-2026-45851)." KEVWire, 6 Nov. 2026, kevwire.com/record/CVE-2026-45851.

Chicago

KEVWire. "Linux kernel: efi: Fix reservation of unaccepted memory table (CVE-2026-45851)." Last modified November 6, 2026. https://kevwire.com/record/CVE-2026-45851.

Evidence summary (plain text)

Linux kernel: efi: Fix reservation of unaccepted memory table (May 27, 2026).
In the Linux kernel, the following vulnerability has been resolved:

efi: Fix reservation of unaccepted memory table

The reserve_unaccepted() function incorrectly calculates the size of the
memblock reservation for the unaccepted memory table. It aligns the
size of the table, but fails to account for cases where the table's
starting physical address (efi.unaccepted) is not page-aligned.

If the table starts at an offset within a page and its end crosses into
a subsequent page that the aligned size does not cover, the end of the
table will not be reserved.
CVSS 7.1 (version 3.1; evidence as of Nov 6, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-45851).
Sources:
NVD CVE-2026-45851: https://nvd.nist.gov/vuln/detail/CVE-2026-45851
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-06T15:21:05.474Z&lastModEndDate=2026-11-06T16:50:56.468Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-06T14:41:02.636Z&lastModEndDate=2026-11-06T16:20:56.228Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-45851.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 6, 2026, 16:50 UTC. Ingestion is not an independent editorial investigation.

NVD status: Analyzed. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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