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VulnerabilityPublished Updated

CVE-2026-89987: Linux kernel · mm/huge_memory: transfer the pmd dirty bit to the folio on zap

Affects Linux kernelSource GCVE Database

0
Authoritative record:CVE-2026-89987

Not known to be exploited · CVSS 5.7 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 4.0 base score
5.7Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

Affected software

ProductAffectedFixed in
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threatsAffected
  • 6.17.0-5.5 – 7.0.0-38.38
23 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threatsAffected
  • 6.17.0-1002.2 – 7.0.0-1014.14
15 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threatsAffected
  • 6.17.0-1003.3 – 7.0.0-1017.17
15 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threatsAffected
  • 7.0.0-1003.3 – 7.0.0-1016.16
9 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threatsAffected
  • 6.17.0-1002.2 – 7.0.0-1014.14
13 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threatsAffected
  • 7.0.0-1002.3 – 7.0.0-1008.9
6 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix for this vulnerability is available in updated Linux Azure kernel versions. Users should upgrade to the patched kernel versions listed in the affectedVersions field to prevent silent data loss. If upgrading is not immediately possible, disabling transparent huge pages or swap may mitigate the issue, but these are not permanent solutions. Check vendor advisories for official patch releases and guidance.

Description

A vulnerability in the Linux kernel's huge memory management subsystem (mm/huge_memory) causes silent data loss for processes using MAP_SHARED tmpfs segments with transparent huge pages (THP) enabled and swap enabled. The issue arises because the pmd dirty bit is not transferred to the folio on zap, leading to dirty pages being incorrectly treated as clean and discarded without being swapped out. This affects scenarios such as shared memory caches across process generations using /dev/shm. The vulnerability has been resolved in specific Linux Azure kernel versions.

References

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