CVE-2026-97515
i3c: master: svc: Prevent IRQ storm from false SLVSTART on NPCM845
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.
INFO
Published Date :
Sept. 24, 2026, 5:17 p.m.
Last Modified :
Sept. 24, 2026, 5:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Clear SLVSTART status bit after emitting STOP for Master Request.
- Disable false SLVSTART interrupt events.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-97515.
| URL | Resource |
|---|---|
| https://git.kernel.org/stable/c/1effa3adfe53cb2bb28bf5640a676b791d5ab405 | |
| https://git.kernel.org/stable/c/e9b139c4684ed8593a0b779ca02ea05f460b2eec |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-97515 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-97515
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-97515 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-97515 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 24, 2026
Action Type Old Value New Value Added 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. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/97xxx/CVE-2026-97515.json">CVE-2026-97515</a> Added Reference https://git.kernel.org/stable/c/1effa3adfe53cb2bb28bf5640a676b791d5ab405 Added Reference https://git.kernel.org/stable/c/e9b139c4684ed8593a0b779ca02ea05f460b2eec