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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-24 · updated 2026-08-17

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.

Affected products

Linux kernel: from 6.6 before 6.6.144; from 6.7 before 6.12.95; from 6.13 before 6.18.37; from 6.19 before 7.0.14; from 7.1 before 7.1.2 — fixed in 6.12.95, 6.18.37, 6.6.144, 7.0.14, 7.1.2

How to fix

Upgrade to a fixed version: Linux kernel 6.12.95, 6.18.37, 6.6.144, 7.0.14. Check the vendor advisory for mitigations.

References

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