CVE-2026-23055: 
Linux Kernel vulnerability analysis and mitigation

CVE-2026-23055 is a vulnerability in the Linux kernel's Renesas I2C (RIIC) driver affecting suspend/resume handling. Specifically, commit 53326135d0e0 ("i2c: riic: Add suspend/resume support") introduced a race condition where I2C transfers can occur after the device has been marked as suspended, triggering a kernel WARNING. The issue manifests on Renesas RZ/G3E hardware (e.g., SMARC EVK based on r9a09g047e57) and is resolved by moving suspend handling to the NOIRQ phase. It was published on February 4, 2026, with a CVSS category estimate of Medium and an EPSS score of 0.000170 (Feedly, CVE.org).

The root cause is improper sequencing of suspend/resume operations in the i2c-riic Linux kernel driver (CWE-362: Race Condition). When the system enters suspend, the I2C subsystem marks the adapter as suspended before all dependent drivers have stopped issuing transfers; this causes a "Transfer while suspended" WARNING in __i2c_smbus_xfer(). The fix moves the RIIC driver's suspend callback to the NOIRQ phase, ensuring no further I2C transactions can be initiated by the time the driver suspends. The vulnerability is local in nature and requires the ability to trigger a system suspend on affected Renesas hardware (Feedly, Linux Kernel Git).

The primary impact is a kernel WARNING that can disrupt system stability during suspend/resume cycles on affected Renesas RZ/G3E platforms. While the WARNING itself does not directly lead to privilege escalation or data exfiltration, it indicates an unsafe state that could result in I2C transaction corruption, incomplete device suspension, or system instability. In embedded or industrial environments relying on Renesas hardware, repeated triggering could degrade reliability or cause denial-of-service conditions during power management operations (Feedly).

The fix is available in the Linux kernel stable tree via patches at the following commits: 0b4c0fbbe00b, 469f8fe4c87e, and e383f0961422f983451ac4dd6aed1a3d3311f2be, which move the RIIC driver's suspend handling to the NOIRQ phase. Users running affected Renesas RZ/G3E systems should apply the relevant kernel patch or update to a kernel version that includes these fixes. As a temporary workaround, avoiding suspend/resume cycles on affected hardware can prevent the WARNING from triggering (Linux Kernel Git).