CVE-2026-97515

Unknown

Last modified

CVE-2026-97515 is a vulnerability of currently unknown severity. 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.

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.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < e9b139c4684ed8593a0b779ca02ea05f460b2eec; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 1effa3adfe53cb2bb28bf5640a676b791d5ab405; < 6.18.53
LinuxLinuxAll versions

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-97515?
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.
How severe is CVE-2026-97515?
Severity scoring for CVE-2026-97515 is pending analysis.
How do I fix CVE-2026-97515?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST