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Vulnerability · Published May 27, 2026 · Assigned by Linux

CVE-2026-45851efi: Fix reservation of unaccepted memory table

High 7.1

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)7.1High
Exploit odds (30 days)0.2%top 94.3% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linux6.12.85-1DEBIAN-CVE-2026-45851
Debian:14linux6.18.14-1DEBIAN-CVE-2026-45851
Ubuntu:24.04:LTSlinux6.8.0-134.134UBUNTU-CVE-2026-45851
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-aws6.8.0-1060.63UBUNTU-CVE-2026-45851
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1060.63~22.04.1UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-azure6.8.0-1063.71UBUNTU-CVE-2026-45851
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1063.71~22.04.1UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1062.69UBUNTU-CVE-2026-45851
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1062.69~22.04.1UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-gcp6.8.0-1063.69UBUNTU-CVE-2026-45851
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1063.69~22.04.1UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-gke6.8.0-1058.64UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1045.48UBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-136.136~22.04.1UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-ibm6.8.0-1060.61UBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1060.61~22.04.1UBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-134.134.1UBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-134.134.1~22.04.1UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1058.61UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1058.61~22.04.1UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1058.61.1UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1029.30UBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-oracle6.8.0-1057.58UBUNTU-CVE-2026-45851
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1057.58~22.04.1UBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-raspi6.8.0-1060.64UBUNTU-CVE-2026-45851
Ubuntu:25.10linux-raspino fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-45851
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-45851
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-134.134~22.04.1UBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-45851
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-45851
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1032.33UBUNTU-CVE-2026-45851

Affected products (as reported)

VendorProductVersions
Linux Linux 8dbe33956d96c9d066ef15ca933ede30748198b2 – before b7bc182ec1846be437351e44164089d988f9d0dd8dbe33956d96c9d066ef15ca933ede30748198b2 – before ba6b6f1502fa55621d1db23f253d54322bdbe4e08dbe33956d96c9d066ef15ca933ede30748198b2 – before 9b18bf59977f5c5bc3b11b210520f62500a7adf38dbe33956d96c9d066ef15ca933ede30748198b2 – before e649b5916725c68f44ebf45fb396df563c5dbaf28dbe33956d96c9d066ef15ca933ede30748198b2 – before 0862438c90487e79822d5647f854977d50381505
Linux Linux 6.6

References