Linux Kernel mem->altmap flaw triggers WARN_ON on failing device register
CVE-2026-64244 Published on July 24, 2026
drivers/base/memory: set mem->altmap after successful device registration
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.
Products Associated with CVE-2026-64244
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Affected Versions
Linux:- Version 1a8c64e110435e44e71bcd50a75663174b575f22 and below 802e113cf120df7208e4c7e604950a85e87120a8 is affected.
- Version 1a8c64e110435e44e71bcd50a75663174b575f22 and below 22dc0d042f02ce82aa61422ea5f232628bfd9e9c is affected.
- Version 1a8c64e110435e44e71bcd50a75663174b575f22 and below 6c25bf4e44a2b6a14332f952bba0974521f5b72d is affected.
- Version 1a8c64e110435e44e71bcd50a75663174b575f22 and below bc3dd82a0ffd488bb902f4c69c3d28fd4088d973 is affected.
- Version 1a8c64e110435e44e71bcd50a75663174b575f22 and below 059ac6252a63edf1cea79bf30bd860a8c264b62c is affected.
- Version 1a8c64e110435e44e71bcd50a75663174b575f22 and below a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a is affected.
- Version 6.6 is affected.
- Before 6.6 is unaffected.
- Version 6.6.144, <= 6.6.* is unaffected.
- Version 6.12.95, <= 6.12.* is unaffected.
- Version 6.18.37, <= 6.18.* is unaffected.
- Version 7.0.14, <= 7.0.* is unaffected.
- Version 7.1.2, <= 7.1.* is unaffected.
- Version 7.2-rc1, <= * is unaffected.