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Vulnerability · Published Sep 5, 2025 · Assigned by Linux

CVE-2025-38733s390/mm: Do not map lowcore with identity mapping

High 7.8

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 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.2%top 93.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: s390/mm: Do not map lowcore with identity mapping Since the identity mapping is pinned to address zero the lowcore is always also mapped to address zero, this happens regardless of the relocate_lowcore command line option. If the option is specified the lowcore is mapped twice, instead of only once. This means that NULL pointer accesses will succeed instead of causing an exception (low address protection still applies, but covers only parts). To fix this never map the first two pages of physical memory with the identity mapping.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linux6.12.48-1DEBIAN-CVE-2025-38733
Debian:13linux6.12.48-1DSA-6008-1
Debian:14linux6.16.5-1DEBIAN-CVE-2025-38733
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-38733
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-intelno fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-38733
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-38733
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-38733

Affected products (as reported)

VendorProductVersions
Linux Linux 32db401965f165f7c44447d0508097f070c8f576 – before 30bf5728bb217a6d1ba73f44094c9b9c6bc9a56732db401965f165f7c44447d0508097f070c8f576 – before 1d7864acd497cb468a998d44631f84896f885e8532db401965f165f7c44447d0508097f070c8f576 – before 93f616ff870a1fb7e84d472cad0af651b18f9f870b99d0e17d6a73a0526f92bc6b54b2b95e67a31d6.10.11 – before 6.11
Linux Linux 6.11

References