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CVE Record

CVE-2026-23221: bus: fsl-mc: fix use-after-free in driver_override_show()

In the Linux kernel, the following vulnerability has been resolved: bus: fsl-mc: fix use-after-free in driver_override_show() The driver_override_show() function reads the driver_override string without holding the device_lock. However, driver_override_store() uses driver_set_override(), which modifies and frees the string while holding the device_lock. This can result in a concurrent use-after-free if the string is freed by the store function while being read by the show function. Fix this by holding the device_lock around the read operation.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2026-23221 is a Linux kernel memory-safety bug in the fsl-mc bus driver. A concurrent read and write of a driver override string can cause use-after-free behavior. The source bundle does not provide CVSS severity, confirmed impact, or active exploitation evidence.

Executive priority

Treat as a kernel maintenance item unless affected fsl-mc platforms are business-critical or internet-facing management workflows depend on them. Lack of severity and exploitation evidence argues against emergency action, but kernel memory-safety fixes should not be ignored.

Technical view

driver_override_show() reads driver_override without device_lock, while driver_override_store() can modify and free it under device_lock through driver_set_override(). This race can produce a concurrent use-after-free. Kernel stable references indicate the fix is to hold device_lock around the read operation.

Likely exposure

Exposure appears limited to Linux kernels containing the affected fsl-mc bus driver path and the listed affected Linux version data. The provided version information is incomplete and commit-oriented, so confirm exposure against vendor kernel packages and backports.

Exploitation context

The bundle marks KEV as false and provides no cited evidence of active exploitation or public weaponization. The practical attack path, required privileges, and real-world impact are not established in the supplied sources.

Researcher notes

The key issue is a locking mismatch around driver_override. The source bundle supports the root cause and fix direction, but not exploitability, privilege requirements, crash reliability, or security impact beyond use-after-free potential.

Mitigation direction

  • Check Linux vendor guidance for patched kernel packages or backported fixes.
  • Prioritize systems using fsl-mc bus support or related hardware platforms.
  • Plan kernel updates through normal maintenance windows unless vendor guidance says otherwise.
  • Track the referenced stable kernel commits for branch-specific fix availability.

Validation and detection

  • Inventory running kernel versions and vendor package build numbers.
  • Confirm whether fsl-mc bus support is present or enabled on relevant systems.
  • Compare vendor kernel changelogs against the referenced stable fix commits.
  • Verify remediation through package metadata or kernel source provenance, not version numbers alone.
Prepared
Confidence
medium
Sources
9

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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2026-23221 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
3Timeline events
0ADP providers
8Source links

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
LinuxLinux1f86a00c1159fd77e66b1bd6ff1a183f4d46f34d, 1f86a00c1159fd77e66b1bd6ff1a183f4d46f34d, 1f86a00c1159fd77e66b1bd6ff1a183f4d46f34d, 1f86a00c1159fd77e66b1bd6ff1a183f4d46f34d, 1f86a00c1159fd77e66b1bd6ff1a183f4d46f34d, 1f86a00c1159fd77e66b1bd6ff1a183f4d46f34d, 1f86a00c1159fd77e66b1bd6ff1a183f4d46f34dunaffected
LinuxLinux5.10, 0, 5.15.201, 6.1.164, 6.6.127, 6.12.74, 6.18.11, 6.19.1, 7.0affected
Weakness

CWE details

No CWE listed

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