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CVE-2026-46092 Linux CVE debrief

A null-pointer dereference vulnerability in the Linux kernel's Realtek rtw88 Wi-Fi driver could cause system crashes during device probe when the 8821CE chipset is installed in systems with a root bus PCI topology. The issue occurs because pci_upstream_bridge() returns NULL when no PCI-to-PCI bridge exists upstream, and the driver previously did not validate this return value before applying a workaround. The vulnerability was discovered by the Linux Verification Center using the Svace static analysis tool. The fix adds a null check before applying the bridge-specific workaround.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-27
Original CVE updated
2026-07-16
Advisory published
2026-05-27
Advisory updated
2026-07-16

Who should care

Linux system administrators deploying 8821CE Wi-Fi hardware in non-standard PCI topologies; embedded systems developers using this chipset; kernel maintainers backporting fixes to stable branches

Technical summary

The rtw88 Wi-Fi driver for Realtek 8821CE chipsets contains a null-pointer dereference vulnerability in its PCI probe routine. The driver calls pci_upstream_bridge() to obtain a reference to the upstream PCI bridge for applying a specific workaround, but does not check if the return value is NULL. When the device is connected directly to a root bus without an intermediate PCI-to-PCI bridge, pci_upstream_bridge() returns NULL, causing a crash when the driver attempts to dereference this pointer. The fix adds a conditional check to verify the bridge exists before applying the workaround. This vulnerability is primarily relevant for systems where the 8821CE card is installed in desktop or server configurations rather than the typical laptop deployment scenario.

Defensive priority

medium

Recommended defensive actions

  • Apply the kernel patch from the stable tree that adds the pci_upstream_bridge() null check
  • Update to a kernel version containing the fix (commit eb101d2abdcccb514ca4fccd3b278dd8267374f6 or later)
  • For systems using 8821CE in non-standard PCI topologies, verify kernel version before deployment
  • Monitor kernel logs for rtw88 probe failures as potential indicators of this issue

Evidence notes

The vulnerability description indicates this was found through static analysis (Svace) rather than active exploitation. The issue affects a specific hardware configuration (8821CE on root bus PCI topology) that is uncommon in typical laptop deployments where this card is usually found.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-46092 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-46092

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

  • CVE-2026-46092 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-46092

    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/eb101d2abdcccb514ca4fccd3b278dd8267374f6

    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.