CVE-2026-64244: Linux kernel · drivers/base/memory: set mem->altmap after successful device registration
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 7.0.0-31.31~24.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 7.0.0-31.31~24.04.1, 7.0.0-31.31, 7.0.0-1012.12 +7
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- ubuntu.com/security/CVE-2026-64244 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64244 (opens in a new tab)
- git.kernel.org/linus/a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a (opens in a new tab)
- git.kernel.org/stable/c/059ac6252a63edf1cea79bf30bd860a8c264b62c (opens in a new tab)
- git.kernel.org/stable/c/22dc0d042f02ce82aa61422ea5f232628bfd9e9c (opens in a new tab)
- git.kernel.org/stable/c/6c25bf4e44a2b6a14332f952bba0974521f5b72d (opens in a new tab)
- git.kernel.org/stable/c/802e113cf120df7208e4c7e604950a85e87120a8 (opens in a new tab)
- git.kernel.org/stable/c/a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a (opens in a new tab)
- git.kernel.org/stable/c/bc3dd82a0ffd488bb902f4c69c3d28fd4088d973 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64244.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-64244 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)