CVE-2026-80951: Linux Vulnerability

Description

In the Linux kernel, the following vulnerability has been resolved: i3c: master: svc: bound IBI payload to the requested max_payload_len svc_i3c_master_handle_ibi() reads the IBI payload from the RX FIFO into the IBI slot. The loop is bounded by the hardware FIFO size (SVC_I3C_FIFO_SIZE), not by the slot size. slot->data points into the IBI pool, which i3c_generic_ibi_alloc_pool() sizes at max_payload_len per slot. svc_i3c_master_request_ibi() only rejects a max_payload_len larger than SVC_I3C_FIFO_SIZE, so a driver can request a smaller one. mctp-i3c requests 1. Each readsb() then copies the controller RXCOUNT bytes (up to 31) with no check against the slot size. A device that sends more bytes than the slot holds writes past slot->data, an out-of-bounds write into the IBI pool. Bound the loop by dev->ibi->max_payload_len and clamp each read to the space left in the slot, the same way dw-i3c does. A device can still send more than the requested payload. Flush the leftover bytes from the RX FIFO so they do not leak into the next transfer.

Metrics

EPSS Probability

0.20%

9.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

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

Vendor	Product	Versions
Linux	Linux	>= dd3c52846d5954acd43f0e771689302f27dadc28, < 7c099b0b292a68d0ef558527945dbfb756fbf893; >= dd3c52846d5954acd43f0e771689302f27dadc28, < 7cc5ba756bc1cfffab9cb2695742f9f479dc73f7; >= dd3c52846d5954acd43f0e771689302f27dadc28, < 35aa6730b8c5626b879a4e893fe664f59bf07d7f; >= dd3c52846d5954acd43f0e771689302f27dadc28, < f296a0d5907bf88314dfda67245f7f69d1552470; >= dd3c52846d5954acd43f0e771689302f27dadc28, < 5697d779577e2786ff3348ae9b77020ac0cf0aab; >= dd3c52846d5954acd43f0e771689302f27dadc28, < aac3c5aababc7fb69d5bf5b0cc52d308574e3a8c; >= dd3c52846d5954acd43f0e771689302f27dadc28, < e2bda39d7f9f285ec803e200b5c1f17143d0b483
Linux	Linux	5.12

References

Timeline

Published: Sep 11, 2026
Last Modified: Sep 14, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-80951?

In the Linux kernel, the following vulnerability has been resolved: i3c: master: svc: bound IBI payload to the requested max_payload_len svc_i3c_master_handle_ibi() reads the IBI payload from the RX FIFO into the IBI slot. The loop is bounded by the hardware FIFO size (SVC_I3C_FIFO_SIZE), not by the slot size. slot->data points into the IBI pool, which i3c_generic_ibi_alloc_pool() sizes at max_payload_len per slot. svc_i3c_master_request_ibi() only rejects a max_payload_len larger than SVC_I3C_FIFO_SIZE, so a driver can request a smaller one. mctp-i3c requests 1. Each readsb() then copies the controller RXCOUNT bytes (up to 31) with no check against the slot size. A device that sends more bytes than the slot holds writes past slot->data, an out-of-bounds write into the IBI pool. Bound the loop by dev->ibi->max_payload_len and clamp each read to the space left in the slot, the same way dw-i3c does. A device can still send more than the requested payload. Flush the leftover bytes from the RX FIFO so they do not leak into the next transfer.

How severe is CVE-2026-80951?

Severity scoring for CVE-2026-80951 is pending analysis. The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2026-80951?

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.

How Strix Helps

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