Kernel use-after-free via irqfd shutdown race
Published Sep 24, 2026 · Updated Sep 24, 2026
Use-after-free in Linux before 6.18.53 allows local users to trigger freed ACRN irqfd access during eventfd shutdown. The acrn_irqfd_deassign path can free struct hsm_irqfd while an EPOLLHUP callback has already queued shutdown work, which later reconstructs and dereferences the dangling object. Reachability requires the ACRN Hypervisor Service Module and access to its irqfd lifecycle; the disclosure establishes unsafe kernel memory access but no further consequence.
Summary
What happened
Use-after-free in Linux before 6.18.53 allows local users to trigger freed ACRN irqfd access during eventfd shutdown. The acrn_irqfd_deassign path can free struct hsm_irqfd while an EPOLLHUP callback has already queued shutdown work, which later reconstructs and dereferences the dangling object. Reachability requires the ACRN Hypervisor Service Module and access to its irqfd lifecycle; the disclosure establishes unsafe kernel memory access but no further consequence.
The record
- CVE
- CVE-2026-97478
- Published
- Sep 24, 2026
- Updated
- Sep 24, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 24, 2026CVE publishedPublication date reported by the CVE source.
- Sep 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <6.18.53
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <666c7f9e07925aa0863348f960e09bb89f8f05a3
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d8156aacfcabb81f52c20ef89094945434d08079
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
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Public exploit references
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Technologies
Your stack
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