VulnerabilityPublished 18 Oct 2026

CVE-2026-98723: Linux kernel · nvmet: copy the hostid into the ctrl before creating PR pc_refs

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in d3d6d7efdacc08616d23b3ac42272a494951dc0f : update Linux kernel when convenient.

Data as of 26 Oct 2026, 10:12 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in d3d6d7efdacc08616d23b3ac42272a494951dc0f, 23194531595c5d1d4454e3a607b0c8fc0c4e8695, 5211fed41d7ec90e9ab7239dc4bffffe4d0b2b62

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 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

Upgrade Linux kernel to d3d6d7efdacc08616d23b3ac42272a494951dc0f, 23194531595c5d1d4454e3a607b0c8fc0c4e8695 or 5211fed41d7ec90e9ab7239dc4bffffe4d0b2b62.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 7b658153f1b8a79ed98980f2fef7b92a66aeb9cd, < d3d6d7efdacc08616d23b3ac42272a494951dc0f	Fixed in d3d6d7efdacc08616d23b3ac42272a494951dc0f
LinuxLinux	Affected ≥ 7b658153f1b8a79ed98980f2fef7b92a66aeb9cd, < 23194531595c5d1d4454e3a607b0c8fc0c4e8695	Fixed in 23194531595c5d1d4454e3a607b0c8fc0c4e8695
LinuxLinux	Affected ≥ 7b658153f1b8a79ed98980f2fef7b92a66aeb9cd, < 5211fed41d7ec90e9ab7239dc4bffffe4d0b2b62	Fixed in 5211fed41d7ec90e9ab7239dc4bffffe4d0b2b62
LinuxLinux	Affected =6.15	Fixed in–

AI-suggested

A fix is available in the Linux kernel as indicated by the fixed commit versions. Users should update to a kernel version that includes the fix (commits d3d6d7efdacc08616d23b3ac42272a494951dc0f, 23194531595c5d1d4454e3a607b0c8fc0c4e8695, or 5211fed41d7ec90e9ab7239dc4bffffe4d0b2b62). No other mitigation is indicated or required.

Description

A vulnerability in the Linux kernel's nvmet subsystem causes the host ID to be copied incorrectly during controller initialization. This results in the host ID stored in per-controller reservation references being a nil UUID. Consequently, the Preempt and Abort mechanism silently degrades to just Preempt, allowing in-flight I/O from a victim host to continue undrained during preemption scenarios.

Impact

The vulnerability causes the Abort operation in the Preempt and Abort mechanism to fail silently, degrading to a simple Preempt. This means that when a host is preempted, its in-flight I/O may not be properly aborted and drained, potentially leading to data consistency or availability issues during namespace reservation scenarios involving reconnects or multiple hosts.

Summary

The Linux kernel nvmet subsystem had a flaw where the host ID (hostid) was copied after the controller was published, causing the per-controller per-namespace reservation references (pc_refs) to store a nil UUID instead of the actual host ID. This occurs because the controller is allocated with kzalloc(), initializing hostid to nil, and the snapshot in nvmet_ctrl_init_pr() happens before the hostid is copied from the connect data. The pc_ref->hostid is used by nvmet_pr_set_ctrl_to_abort() to match and abort in-flight I/O for Preempt and Abort operations. Due to the nil UUID, the match fails, and Abort silently degrades to Preempt, meaning the victim's in-flight I/O is not properly killed and drained. The fix involves copying the hostid earlier, before the controller is published and before nvmet_ctrl_init_pr() takes its snapshot.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:59 UTC

Technical details

References

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