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CVE Record

CVE-2026-23148: nvmet: fix race in nvmet_bio_done() leading to NULL pointer dereference

In the Linux kernel, the following vulnerability has been resolved: nvmet: fix race in nvmet_bio_done() leading to NULL pointer dereference There is a race condition in nvmet_bio_done() that can cause a NULL pointer dereference in blk_cgroup_bio_start(): 1. nvmet_bio_done() is called when a bio completes 2. nvmet_req_complete() is called, which invokes req->ops->queue_response(req) 3. The queue_response callback can re-queue and re-submit the same request 4. The re-submission reuses the same inline_bio from nvmet_req 5. Meanwhile, nvmet_req_bio_put() (called after nvmet_req_complete) invokes bio_uninit() for inline_bio, which sets bio->bi_blkg to NULL 6. The re-submitted bio enters submit_bio_noacct_nocheck() 7. blk_cgroup_bio_start() dereferences bio->bi_blkg, causing a crash: BUG: kernel NULL pointer dereference, address: 0000000000000028 #PF: supervisor read access in kernel mode RIP: 0010:blk_cgroup_bio_start+0x10/0xd0 Call Trace: submit_bio_noacct_nocheck+0x44/0x250 nvmet_bdev_execute_rw+0x254/0x370 [nvmet] process_one_work+0x193/0x3c0 worker_thread+0x281/0x3a0 Fix this by reordering nvmet_bio_done() to call nvmet_req_bio_put() BEFORE nvmet_req_complete(). This ensures the bio is cleaned up before the request can be re-submitted, preventing the race condition.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A race condition in the Linux NVMe target subsystem can crash the kernel, disrupting storage services and dependent workloads. The supplied CVSS 3.1 score is 7.5 because the documented impact is availability loss, with no stated confidentiality or integrity impact.

Executive priority

Treat this as a high-priority availability issue for organizations using Linux NVMe targets. Patch internet-reachable, shared-storage, or business-critical target hosts first. Systems not using nvmet are less likely to be exposed, but version and configuration validation is necessary before lowering priority.

Technical view

In nvmet_bio_done(), response handling could requeue and resubmit a request before its inline bio was cleaned up. Subsequent cleanup set bi_blkg to NULL while the reused bio was entering submission, causing blk_cgroup_bio_start() to dereference NULL. The fix moves nvmet_req_bio_put() before nvmet_req_complete().

Likely exposure

Exposure is most likely on Linux systems operating the NVMe target subsystem, particularly where requests use the affected inline-bio lifecycle. The supplied version data is difficult to interpret reliably, so assess deployed kernel builds against the cited stable commits rather than relying only on version strings.

Exploitation context

The supplied vector describes network reachability, low complexity, no privileges, and no user interaction, with availability impact only. However, the bundle provides no exploit demonstration or operational attack details. The CVE is not listed as KEV, and the supplied evidence does not establish active exploitation.

Researcher notes

The failure is a use-order race involving request completion, callback-driven resubmission, inline_bio reuse, and later bio_uninit() cleanup. The supplied record identifies three stable-kernel commits, but its affected-version fields appear ambiguous. Confirm ancestry or vendor backport status before declaring a specific build vulnerable or fixed.

Mitigation direction

  • Apply a vendor-supported kernel release containing the cited nvmet fix.
  • Prioritize exposed or business-critical NVMe target hosts.
  • Check Linux distribution advisories for backported fixes and exact package versions.
  • Restrict NVMe target access to trusted initiators and networks where operationally feasible.

Validation and detection

  • Inventory systems running or configured for the Linux NVMe target subsystem.
  • Record kernel package versions, build identifiers, and distribution advisory status.
  • Confirm the deployed kernel includes an applicable cited stable fix.
  • Review kernel logs for nvmet-related NULL dereferences and unexpected storage-host crashes.
  • After updating, verify NVMe target workloads and failover behavior in controlled testing.
Prepared
Confidence
high
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2026-23148 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
0ADP providers
4Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-23148Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux431e58d56fcb5ff1f9eb630724a922e0d2a941df, 190f4c2c863af7cc5bb354b70e0805f06419c038, 190f4c2c863af7cc5bb354b70e0805f06419c038, 2e2028fcf924d1c6df017033c8d6e28b735a0508, 6.12.37, 6.15.6unaffected
LinuxLinux6.16, 0, 6.12.69, 6.18.9, 6.19affected
Weakness

CWE details

No CWE listed

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