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CVE Record

CVE-2026-46092: wifi: rtw88: check for PCI upstream bridge existence

In the Linux kernel, the following vulnerability has been resolved: wifi: rtw88: check for PCI upstream bridge existence pci_upstream_bridge() returns NULL if the device is on a root bus. If 8821CE is installed in the system with such a PCI topology, the probing routine will crash. This has probably been unnoticed as 8821CE is mostly supplied in laptops where there is a PCI-to-PCI bridge located upstream from the device. However the card might be installed on a system with different configuration. Check if the bridge does exist for the specific workaround to be applied. Found by Linux Verification Center (linuxtesting.org) with Svace static analysis tool.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2026-46092 is a Linux kernel crash bug in the Realtek rtw88 Wi-Fi driver path. On systems where an 8821CE PCI Wi-Fi device sits on a root bus without an upstream bridge, driver probing can crash the kernel. This appears to be a narrow availability issue tied to specific hardware topology.

Executive priority

Treat as a targeted availability risk, not an emergency internet-facing issue based on current evidence. Patch through normal kernel maintenance, with higher priority for fleets using Realtek 8821CE Wi-Fi cards or custom PCI configurations.

Technical view

The rtw88 PCI probe logic assumed pci_upstream_bridge() returned a bridge. For root-bus devices it can return NULL, and the 8821CE workaround path could dereference that missing bridge and crash. The fix checks that the upstream bridge exists before applying the workaround. The CVE record lists Linux kernel stable commit references as fixes.

Likely exposure

Exposure is most likely on Linux systems using affected kernel versions with Realtek 8821CE PCI Wi-Fi hardware installed in a topology lacking a PCI-to-PCI upstream bridge. The source notes this may be uncommon in laptops, where an upstream bridge is usually present.

Exploitation context

No source in the bundle reports active exploitation, public exploit use, or KEV listing. The described trigger is driver probing under a specific PCI topology, causing a crash rather than code execution. Evidence supports availability impact, but not remote attackability.

Researcher notes

The key condition is a NULL return from pci_upstream_bridge() during rtw88 8821CE probing. The source bundle does not provide CVSS, CWE, distro package status, or crash trace details. Analysis should stay limited to topology-dependent kernel crash risk unless additional vendor evidence emerges.

Mitigation direction

  • Apply a vendor or distribution kernel update containing the referenced stable fixes.
  • Prioritize systems with Realtek 8821CE PCI Wi-Fi hardware and affected kernel versions.
  • Check Linux vendor advisories for exact fixed package versions before rollout.
  • Avoid deploying affected hardware in the described PCI topology until patched, where practical.

Validation and detection

  • Inventory Linux hosts for Realtek 8821CE hardware using the rtw88 PCI driver.
  • Confirm whether kernel versions fall within the affected ranges listed by the CVE record.
  • Review PCI topology for devices attached to a root bus without an upstream bridge.
  • Verify installed kernel packages include the referenced upstream stable commits.
Prepared
Confidence
high
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

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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
LinuxLinux617339466fda09916c4b4151fa5e6a9c1fdae353, 24f5e38a13b5ae2b6105cda8bb47c19108e62a9a, 24f5e38a13b5ae2b6105cda8bb47c19108e62a9a, 24f5e38a13b5ae2b6105cda8bb47c19108e62a9a, 24f5e38a13b5ae2b6105cda8bb47c19108e62a9a, 24f5e38a13b5ae2b6105cda8bb47c19108e62a9a, 24f5e38a13b5ae2b6105cda8bb47c19108e62a9a, f21e8cb927fa9da49490b74ddda3856a828b82d6, 5.15.17, 5.16.3unaffected
LinuxLinux5.17, 0, 5.15.210, 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1affected
Weakness

CWE details

No CWE listed

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