VulnerabilityPublished 17 Sep 2026Updated 5 Oct 2026

CVE-2026-93066: Linux kernel · x86/mm/pat: Take cpa_lock around large-page collapse

Affects Linux kernelSource GCVE Database

Authoritative record:CVE-2026-93066· High

Not known to be exploited.

Data as of 26 Oct 2026, 14:05 UTC

Severity

High

Rated by Threat Radar · CVSS not yet scored by NVD

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.

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Sep 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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-38.38 23 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected 6.17.0-1003.3 – 7.0.0-1017.17 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected 7.0.0-1003.3 – 7.0.0-1016.16 9 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 13 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected 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 is available that serializes the large-page collapse operations under the cpa_lock to prevent concurrent access to freed page-table pages. Users should update to patched kernel versions that include this fix. No additional mitigations are indicated.

Description

A use-after-free vulnerability in the Linux kernel's x86 memory management subsystem was resolved by serializing large-page collapse operations under a lock. The flaw allowed concurrent module loading and unloading on multiple CPUs to cause a stale pointer dereference, leading to memory corruption or faults. This issue affected specific Linux kernel versions used in Ubuntu HWE edge releases. The vulnerability is rated medium severity.

Impact

Exploitation of this vulnerability can cause use-after-free memory corruption in the kernel's page table management, potentially leading to system instability, crashes, or data corruption. The issue arises during concurrent module load/unload operations on affected kernel versions. There is no indication of known exploits in the wild.

Summary

CVE-2026-93066 is a use-after-free vulnerability in the Linux kernel's x86/mm/pat subsystem related to large-page collapse during concurrent loading and unloading of kernel modules on KASAN builds. The flaw occurs because cpa_collapse_large_pages() rebuilds a leaf PMD and frees old PTE-table pages while __change_page_attr() concurrently fetches and writes to a PTE pointer obtained via a lockless lookup. This results in writes to freed memory, causing corruption or faults. The root cause is that flush_tlb_all() does not serialize against page-table walkers running with interrupts enabled. The fix was to serialize the PMD rebuild, TLB flush, and PTE-table free operations under the cpa_lock, which __change_page_attr() now always takes, preventing concurrent access to freed page-table pages.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Oct 2026, 23:27 UTC

Technical details

References

Community reviews

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