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PatchSiren cyber security CVE debrief

CVE-2026-46203 Linux CVE debrief

A vulnerability in the Linux kernel's Cadence Quad SPI (QSPI) driver could allow unclocked register access during driver unbind operations. The issue occurs when the controller is not runtime resumed before being disabled, potentially leading to undefined behavior or system instability. The fix ensures proper runtime power management state before controller disablement.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-28
Original CVE updated
2026-06-19
Advisory published
2026-05-28
Advisory updated
2026-06-19

Who should care

Organizations running Linux on embedded systems or hardware utilizing Cadence QSPI controllers, particularly those with hot-pluggable or dynamically bound SPI devices. Relevant for IoT device manufacturers, industrial control systems, and embedded Linux distributions.

Technical summary

The Cadence Quad SPI driver in the Linux kernel failed to ensure the controller was runtime resumed before disabling it during driver unbind. This created a window where register accesses could occur without proper clocking, constituting an unclocked access vulnerability. The fix adds proper runtime resume synchronization before controller disablement.

Defensive priority

medium

Recommended defensive actions

  • Apply kernel updates containing the referenced stable commits when available for your distribution
  • Monitor vendor security advisories for kernel package updates
  • Review systems using Cadence QSPI controllers for stability concerns during driver unload operations
  • Validate runtime power management behavior in embedded/IoT deployments using this driver

Evidence notes

The vulnerability was identified during review of a controller deregistration fix by Sashiko. The resolution involves ensuring the controller is runtime resumed before disabling it during driver unbind to prevent unclocked register access. Two kernel commits address this issue for stable kernel branches.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-46203 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-46203

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-46203 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-46203

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/233db2cb14db8b1935dda52a6affd97276462b82

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/d67a5311818b3e6481a1e4293c9337ebfee73111

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.