CVE-2026-45851

efi: Fix reservation of unaccepted memory table

HIGH
7.1
CVSS Score
Published: May 27, 2026 at 12:15 PM UTC
Updated: June 27, 2026 at 11:41 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.1
Exploit prediction
EPSS 0.2%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.13 ≤ v < 6.18.146.19 ≤ v < 6.19.46.6 ≤ v < 6.12.756.6 ≤ v < 6.18.146.6 ≤ v < 6.19.46.6 ≤ v < 6.6.1286.6 ≤ v < 7.06.6.1 ≤ v < 6.6.1286.7 ≤ v < 6.12.756.66.6 rc36.6 rc46.6 rc56.6 rc66.6 rc78dbe33956d96c9d066ef15ca933ede30748198b2
Vendor states this is fixed in 0862438c90487e79822d5647f854977d50381505 (fixed)
Vendor states this is fixed in 9b18bf59977f5c5bc3b11b210520f62500a7adf3 (fixed)
Vendor states this is fixed in b7bc182ec1846be437351e44164089d988f9d0dd (fixed)
Vendor states this is fixed in ba6b6f1502fa55621d1db23f253d54322bdbe4e0 (fixed)
Vendor states this is fixed in e649b5916725c68f44ebf45fb396df563c5dbaf2 (fixed)
Vendor states this is fixed in 6.12.75 (unaffected)
Vendor states this is fixed in 6.18.14 (unaffected)
Vendor states this is fixed in 6.19.4 (unaffected)
Vendor states this is fixed in 6.6 (unaffected)
Vendor states this is fixed in 6.6.128 (unaffected)
Vendor states this is fixed in 7.0 (unaffected)

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-125

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