CVE-2026-97515

Received Received - Intake

BaseFortify

Publication date: 2026-09-24

Last updated on: 2026-09-28

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: i3c: master: svc: Prevent IRQ storm from false SLVSTART on NPCM845 On NPCM845, when a target on the I3C bus gets stuck holding SDA low, the controller reports a false Master Request (MR) in-band interrupt event. The driver handles this by emitting a STOP condition to restore the bus. However, the hardware quirk SVC_I3C_QUIRK_FALSE_SLVSTART indicates that emitting a STOP condition may spuriously set the SLVSTART interrupt status bit. In the Master Request case, this creates a feedback loop: the STOP triggers a new SLVSTART event, the IRQ handler fires again, the controller still reports an MR type, another STOP is emitted, and the cycle repeats indefinitely, resulting in an IRQ storm that can lock up the CPU. Clear the SLVSTART status bit explicitly after emitting the STOP in the Master Request IBI handler when the SVC_I3C_QUIRK_FALSE_SLVSTART quirk is set. This breaks the feedback loop without affecting normal SLVSTART processing, which is already guarded in the top-level IRQ handler by checking that MSTATUS is in SLVREQ state.

CVSS Scores

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Meta Information

Published

2026-09-24

Last Modified

2026-09-28

Generated

2026-10-15

AI Q&A

2026-09-24

EPSS Evaluated

2026-10-13

NVD

CVE-2026-97515

EUVD

EUVD-2026-86113

Affected Vendors & Products

Vendor	Product	Version / Range
Linux	Linux	0430bf9bc1ac068c8b8c540eb93e5751872efc51
Linux	Linux	0430bf9bc1ac068c8b8c540eb93e5751872efc51
Linux	Linux	30748ce7e156f221fb91689b338a0d7df77b732a
Linux	Linux	f2985a1de6f53abbc42c7a696ee6ba8bdecc9426
Linux	Linux	0541822045ae043d62c941ca31fa76871e436b5e
Linux	Linux	1ea4653cff35c29d1dd0b14ad9c8245e7318f337
Linux	Linux	d231fb443d8d4042f0dd705b93beba8c916a7344
Linux	Linux	5.15.185
Linux	Linux	6.1.141
Linux	Linux	6.6.93
Linux	Linux	6.12.31
Linux	Linux	6.14.9
Linux	Linux	6.15

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability affects the Linux kernel's I3C bus controller driver on NPCM845 systems. When a device on the I3C bus gets stuck holding the SDA line low, the controller falsely reports a Master Request interrupt. The driver attempts to fix this by sending a STOP condition, but a hardware quirk causes the SLVSTART interrupt status bit to be set again, creating an infinite loop of interrupts that locks up the CPU.

Detection Guidance

This vulnerability is specific to Linux kernel I3C bus handling on NPCM845 hardware. Detection requires checking kernel logs for repeated SLVSTART interrupts or IRQ storms on the I3C bus. Monitor dmesg or /var/log/kern.log for messages indicating I3C controller issues or IRQ flooding.

Impact Analysis

This vulnerability can cause system instability by triggering an interrupt storm that consumes CPU resources indefinitely. This may lead to system freezes, unresponsiveness, or crashes, particularly on systems using NPCM845 with I3C bus devices.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it pertains to a hardware-level interrupt storm in the Linux kernel's I3C bus driver. Compliance impacts would depend on system-specific implementations rather than the vulnerability itself.

Mitigation Strategies

Apply the Linux kernel patch that clears the SLVSTART status bit after STOP emission in the Master Request IBI handler. Update to a kernel version containing the fix for CVE-2026-97515. If immediate patching is not possible, disable I3C bus operations on NPCM845 systems until the update is applied.

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