CVE-2026-45851
HighCVSS 7.1Exploitation Probability (EPSS)
Low risk5th percentile - higher than 5% of all known CVEs
Summary
A vulnerability has been identified in the Linux kernel within the reserve_unaccepted() function, which incorrectly calculates the memory reservation size for the unaccepted memory table. This issue can lead to the table being overwritten or inaccessible, resulting in a kernel panic.
Risk Assessment
Organizations may experience critical system failures, especially when starting Intel TDX VMs with specific memory sizes, potentially leading to data loss and downtime.
Recommendation
It is recommended to update the Linux kernel to a version that includes a fix for this vulnerability to ensure proper memory reservation calculations.
Original NVD description (English source)
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.