CVE-2026-89728: i3c: renesas: Fix out-of-bounds access for newdevs mask
In the Linux kernel, the following vulnerability has been resolved:
i3c: renesas: Fix out-of-bounds access for newdevs mask
When software initiates DAA (Dynamic Address Assignment), the controller reports the result via the NRSPQP (Normal Response Queue Port Register). The data length field of the response descriptor, which is accessible through the NRSPQP register, indicates the number of devices remaining after DAA. Consequently, when the bus is empty, this field contains the maximum number of devices supported by the controller (8 for the Renesas I3C controller).
Adjust the condition that computes the newly discovered devices bitmask to prevent an out-of-bounds when the I3C bus is empty.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1
Event History
Frequently Asked Questions
When can this out-of-bounds access occur?
It can occur when software initiates Dynamic Address Assignment on an empty I3C bus. In that case, the controller reports its maximum supported device count, which is 8 for the Renesas I3C controller, in the response descriptor data-length field.
Which systems are exposed to this condition?
Systems using the Renesas I3C controller and initiating Dynamic Address Assignment are affected by the described condition. The problematic case specifically requires that the I3C bus be empty when DAA is performed.