I/O fencing bypass via uninitialized reservation host IDs
Published Oct 18, 2026 · Updated Oct 18, 2026
Reservation handling in Linux 6.15 nvmet allows attackers to retain in-flight I/O after Preempt and Abort via late host-ID copying. nvmet_ctrl_init_pr() copies the controller's zero host ID into reservation references before nvmet_alloc_ctrl() initializes it, preventing nvmet_pr_set_ctrl_to_abort() from matching the victim. A reservation-enabled namespace must exist before connection, including reconnection; preemption reports success without draining the victim's outstanding I/O.
Summary
What happened
Reservation handling in Linux 6.15 nvmet allows attackers to retain in-flight I/O after Preempt and Abort via late host-ID copying. nvmet_ctrl_init_pr() copies the controller's zero host ID into reservation references before nvmet_alloc_ctrl() initializes it, preventing nvmet_pr_set_ctrl_to_abort() from matching the victim. A reservation-enabled namespace must exist before connection, including reconnection; preemption reports success without draining the victim's outstanding I/O.
The record
- CVE
- CVE-2026-98723
- Published
- Oct 18, 2026
- Updated
- Oct 18, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 18, 2026CVE publishedPublication date reported by the CVE source.
- Oct 18, 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=6.15
- Affected versionversion=7b658153f1b8a79ed98980f2fef7b92a66aeb9cd <23194531595c5d1d4454e3a607b0c8fc0c4e8695
- Affected versionversion=7b658153f1b8a79ed98980f2fef7b92a66aeb9cd <5211fed41d7ec90e9ab7239dc4bffffe4d0b2b62
- Affected versionversion=7b658153f1b8a79ed98980f2fef7b92a66aeb9cd <d3d6d7efdacc08616d23b3ac42272a494951dc0f
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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Your stack
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