CVE-2026-64244 drivers/base/memory: set mem->altmap after successful device registration

What is CVE-2026-64244?

CVE-2026-64244 is a medium-severity vulnerability in Linux kernel, published on 24 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

drivers/base/memory: set mem->altmap after successful device registration

If __add_memory_block() fails at xa_store() (under memory pressure for example), device_unregister() is called, which eventually triggers memory_block_release() with mem->altmap still set, causing a WARN_ON(mem->altmap). This was triggered by modifying virtio-mem driver.

Fix this by delaying the assignment of mem->altmap until after __add_memory_block() has succeeded.

Which versions are affected by CVE-2026-64244?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64244?

Apply the vendor's patch.

Is CVE-2026-64244 being exploited?

There is no known exploitation of CVE-2026-64244 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-64244, DEBIAN-CVE-2026-64244, GHSA-837v-fg39-rfww, ROOT-OS-UBUNTU-2204-CVE-2026-64244, UBUNTU-CVE-2026-64244.