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CVE-2026-90208 Linux CVE debrief

A Linux kernel vulnerability was addressed in clocksource/drivers/samsung_pwm by switching to raw_spinlock_t type. This change ensures non-sleeping spinlock usage in atomic contexts like hard interrupt handlers when PREEMPT_RT is enabled on ARM. The update prevents potential issues with clock source functionality on legacy systems utilizing PREEMPT_RT on ARM. Defenders and administrators should assess exposure and apply patches to prevent potential clock source instability. The vulnerability highlights the importance of proper spinlock usage in atomic contexts to maintain system stability.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-17
Original CVE updated
2026-10-19
Advisory published
2026-09-17
Advisory updated
2026-10-19

Who should care

Defenders and administrators responsible for Linux kernel systems, especially those utilizing PREEMPT_RT on ARM, should assess exposure and apply patches to prevent potential issues with clock source functionality.

Why it matters

CVE-2026-90208 is a Linux kernel vulnerability requiring patching to prevent potential issues in clock source functionality, especially on systems using PREEMPT_RT on ARM. Defenders should verify exposure, apply patches, and monitor system behavior.

  • Verify and apply patches for impacted Linux kernel versions to ensure system stability.
  • Assess exposure and prioritize patching for systems using PREEMPT_RT on ARM.
  • Monitor clock source functionality for unusual behavior post-patching.

Technical summary

The Linux kernel vulnerability CVE-2026-90208 was resolved by switching to raw_spinlock_t type in clocksource/drivers/samsung_pwm. This change ensures proper spinlock usage in atomic contexts when PREEMPT_RT is enabled on ARM, preventing potential issues in clock source functionality. The update is crucial for maintaining system stability on legacy systems using PREEMPT_RT on ARM. Defenders should prioritize verifying and applying patches for Linux kernel versions impacted by this vulnerability to prevent potential clock source instability.

Defensive priority

Defenders should prioritize verifying and applying patches for Linux kernel versions impacted by this vulnerability, particularly those using PREEMPT_RT on ARM, to prevent potential issues in clock source functionality.

Recommended defensive actions

  • Verify Linux kernel versions for potential exposure, especially those using PREEMPT_RT on ARM.
  • Apply patches or updates provided by Linux for clocksource/drivers/samsung_pwm.
  • Monitor system logs for unusual activity related to clock source functionality.
  • Review compensating controls for exposed systems while remediation is scheduled and verified.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented.
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and source item provide details on the Linux kernel vulnerability and its resolution by switching to raw_spinlock_t type in clocksource/drivers/samsung_pwm. However, specific exploitation or impact details are not provided, requiring verification from official sources.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-90208 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-90208

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

  • CVE-2026-90208 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-90208

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

Supplemental references

  • clocksource/drivers/samsung_pwm: Switch to raw_spinlock_t type

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/90xxx/CVE-2026-90208.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/a25ea67a913f98b8461aff1e9e3a5f6dc2378395

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/7eb5764d25c4ac7f5d126621660f7219b61fd2fd

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/3b212f9d70805d91febae01d618868f4860e267c

    Supplemental source

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.