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CVE-2026-72212
mm/memory_hotplug: fix incorrect altmap passing in error path
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem mm. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-72212 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
In create_altmaps_and_memory_blocks(), when arch_add_memory() succeeds with memmap_on_memory enabled, the vmemmap pages are allocated from params.altmap. If create_memory_block_devices() subsequently fails, the error path calls arch_remove_memory() with a NULL altmap instead of params.altmap. This is a bug that could lead to memory corruption. Since altmap is NULL, vmemmap_free() falls back to freeing the vmemmap pages into the system buddy allocator via free_pages() instead of the altmap. arch_remove_memory() then immediately destroys the physical linear mapping for this memory. This injects unowned pages into the buddy allocator, causing machine checks or memory corruption if the system later attempts to allocate and use those freed pages. Fix this by passing params.altmap to arch_remove_memory() in the error path.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
mm/memory_hotplug.c
- What this is
- MEMORY HOT(UN)PLUGMAINTAINERS section matched on mm/memory_hotplug.c · linux-mm@kvack.org · Maintained
Show whether Debian builds this, per release
Not established. This site could not find the build rule for the affected file in the kernel trees Debian ships, so it has no answer about whether Debian compiles this code. Read that as unknown, never as absent.
- bookworm, trixie, forky, sid?
- ?
- not established - no Makefile entry for the affected file
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- no vector published, unrated
- Attack vector
- not published
- EPSS
- 0.21%, higher than 10.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- mm
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.8 | 6.12.97 | 3833e6abdbbf |
| 6.8 | 6.18.40 | 722e6c54bde6 |
| 6.8 | 7.1.5 | 2f9e3ec17c3d |
| 6.8 | 7.2 | 2fac4afa0e2e |
Why the CNA scored it this way
The kernel CNA published no CVSS vector and no reasoning for CVE-2026-72212, which is why it is shown as unrated rather than given an invented score. 6,405 of the 20,413 CVEs here carry reasoning; this is not one of them.