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CVE Record

CVE-2026-23055: i2c: riic: Move suspend handling to NOIRQ phase

In the Linux kernel, the following vulnerability has been resolved: i2c: riic: Move suspend handling to NOIRQ phase Commit 53326135d0e0 ("i2c: riic: Add suspend/resume support") added suspend support for the Renesas I2C driver and following this change on RZ/G3E the following WARNING is seen on entering suspend ... [ 134.275704] Freezing remaining freezable tasks completed (elapsed 0.001 seconds) [ 134.285536] ------------[ cut here ]------------ [ 134.290298] i2c i2c-2: Transfer while suspended [ 134.295174] WARNING: drivers/i2c/i2c-core.h:56 at __i2c_smbus_xfer+0x1e4/0x214, CPU#0: systemd-sleep/388 [ 134.365507] Tainted: [W]=WARN [ 134.368485] Hardware name: Renesas SMARC EVK version 2 based on r9a09g047e57 (DT) [ 134.375961] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 134.382935] pc : __i2c_smbus_xfer+0x1e4/0x214 [ 134.387329] lr : __i2c_smbus_xfer+0x1e4/0x214 [ 134.391717] sp : ffff800083f23860 [ 134.395040] x29: ffff800083f23860 x28: 0000000000000000 x27: ffff800082ed5d60 [ 134.402226] x26: 0000001f4395fd74 x25: 0000000000000007 x24: 0000000000000001 [ 134.409408] x23: 0000000000000000 x22: 000000000000006f x21: ffff800083f23936 [ 134.416589] x20: ffff0000c090e140 x19: ffff0000c090e0d0 x18: 0000000000000006 [ 134.423771] x17: 6f63657320313030 x16: 2e30206465737061 x15: ffff800083f23280 [ 134.430953] x14: 0000000000000000 x13: ffff800082b16ce8 x12: 0000000000000f09 [ 134.438134] x11: 0000000000000503 x10: ffff800082b6ece8 x9 : ffff800082b16ce8 [ 134.445315] x8 : 00000000ffffefff x7 : ffff800082b6ece8 x6 : 80000000fffff000 [ 134.452495] x5 : 0000000000000504 x4 : 0000000000000000 x3 : 0000000000000000 [ 134.459672] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c9ee9e80 [ 134.466851] Call trace: [ 134.469311] __i2c_smbus_xfer+0x1e4/0x214 (P) [ 134.473715] i2c_smbus_xfer+0xbc/0x120 [ 134.477507] i2c_smbus_read_byte_data+0x4c/0x84 [ 134.482077] isl1208_i2c_read_time+0x44/0x178 [rtc_isl1208] [ 134.487703] isl1208_rtc_read_time+0x14/0x20 [rtc_isl1208] [ 134.493226] __rtc_read_time+0x44/0x88 [ 134.497012] rtc_read_time+0x3c/0x68 [ 134.500622] rtc_suspend+0x9c/0x170 The warning is triggered because I2C transfers can still be attempted while the controller is already suspended, due to inappropriate ordering of the system sleep callbacks. If the controller is autosuspended, there is no way to wake it up once runtime PM disabled (in suspend_late()). During system resume, the I2C controller will be available only after runtime PM is re-enabled (in resume_early()). However, this may be too late for some devices. Wake up the controller in the suspend() callback while runtime PM is still enabled. The I2C controller will remain available until the suspend_noirq() callback (pm_runtime_force_suspend()) is called. During resume, the I2C controller can be restored by the resume_noirq() callback (pm_runtime_force_resume()). Finally, the resume() callback re-enables autosuspend. As a result, the I2C controller can remain available until the system enters suspend_noirq() and from resume_noirq().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2026-23055 is a Linux kernel issue in the Renesas RIIC I2C driver. During system suspend, the driver can suspend too early, while other components still need I2C access. This can trigger kernel warnings and may disrupt suspend/resume reliability on affected Renesas-based systems.

Executive priority

Schedule remediation for affected Renesas-based Linux platforms, especially products depending on reliable suspend/resume. This is not currently evidenced as internet-exploited, but it can affect device stability and field reliability.

Technical view

The issue is improper power-management callback ordering in the Linux Renesas RIIC I2C driver after commit 53326135d0e0 added suspend/resume support. I2C transfers may occur after the controller is suspended. The fix moves suspend handling to the NOIRQ phase and restores the controller earlier during resume.

Likely exposure

Most relevant to Linux systems using the Renesas RIIC I2C controller, specifically source evidence references RZ/G3E hardware. General Linux servers without this driver or hardware are unlikely to be exposed.

Exploitation context

No active exploitation is indicated in the provided sources, and the CVE is not marked KEV. The described impact is reliability during suspend/resume, not a documented remote attack path.

Researcher notes

Severity, CVSS, and CWE are not provided in the source bundle. Affected version data is limited and should be confirmed against kernel stable branches and downstream distro backports. The public fix rationale is clear, but exploitability beyond suspend/resume disruption is not established.

Mitigation direction

  • Review vendor or distribution kernel guidance for CVE-2026-23055.
  • Update to a kernel containing the referenced stable fixes.
  • Prioritize embedded or edge devices using Renesas RIIC I2C hardware.
  • If updates are unavailable, evaluate operational need for suspend/resume on affected devices.

Validation and detection

  • Inventory Linux devices using Renesas RIIC I2C hardware or driver support.
  • Check kernel version and downstream patch status against vendor advisories.
  • Review suspend/resume logs for “Transfer while suspended” I2C warnings.
  • Confirm the referenced stable commits are present in the deployed kernel tree.
Prepared
Confidence
medium
Sources
5

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

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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
4Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

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  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux53326135d0e041ebe7d08bf22f82529ae69a096e, 53326135d0e041ebe7d08bf22f82529ae69a096e, 53326135d0e041ebe7d08bf22f82529ae69a096eunaffected
LinuxLinux6.12, 0, 6.12.67, 6.18.7, 6.19affected
Weakness

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