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PatchSiren cyber security CVE debrief

CVE-2026-53400 Linux CVE debrief

A Linux kernel vulnerability has been resolved in the i2c core, addressing an adapter registration race condition. The issue arises from the lookup of adapters based on their ID using i2c_get_adapter(), which takes a reference to the embedded struct device. To prevent accessing uninitialized data, which could lead to NULL-pointer dereferences or use-after-free, the adapter must be fully initialized before being added to the IDR. This is crucial because the i2c-dev chardev, registered from a bus notifier, uses i2c_get_adapter(). Therefore, the adapter needs to be added to the IDR before the chardev registration.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-19
Original CVE updated
2026-07-19
Advisory published
2026-07-19
Advisory updated
2026-07-19

Who should care

System administrators and security teams responsible for Linux kernel-based systems should be aware of this vulnerability. The issue affects the Linux kernel's i2c core, which is used for inter-integrated circuit communication. Successful exploitation could lead to system crashes or potential code execution.

Technical summary

The Linux kernel's i2c core has a vulnerability related to adapter registration. Adapters are looked up by their ID using i2c_get_adapter(), which references the embedded struct device. To avoid accessing uninitialized data, adapters must be fully initialized before being added to the IDR. This is particularly important because the i2c-dev chardev uses i2c_get_adapter() and the adapter must be in the IDR before chardev registration.

Defensive priority

Medium

Recommended defensive actions

  • Inventory Linux kernel-based systems for potential exposure.
  • Apply vendor patches or updates to address the i2c core adapter registration race condition.
  • Monitor system logs for unusual i2c-related activity.
  • Consider implementing compensating controls, such as restricting access to i2c devices.
  • Perform a thorough review of system configurations to ensure secure i2c device usage.
  • Verify that all i2c devices are properly configured and secured.
  • Track and document changes to i2c device configurations and monitor for any suspicious activity.

Evidence notes

The CVE record was published on 2026-07-19T12:16:51.177Z and has not been modified since then. The NVD entry is currently Received. Multiple source references are provided, including links to specific kernel commits addressing the issue.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-19T12:16:51.177Z and has not been modified since then. The NVD entry is currently Received.