Bug 2482138 (CVE-2026-45851) - CVE-2026-45851 kernel: efi: Fix reservation of unaccepted memory table
Summary: CVE-2026-45851 kernel: efi: Fix reservation of unaccepted memory table
Keywords:
Status: NEW
Alias: CVE-2026-45851
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-27 15:13 UTC by OSIDB Bzimport
Modified: 2026-05-28 04:55 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-05-27 15:13:08 UTC
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().

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.


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