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CVE-2026-80951

i3c: master: svc: bound IBI payload to the requested max_payload_len

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, and 1 more
None on Exploit-DB, Metasploit or GitHub

Summary

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From dd3c52846d5954acd43f0e771689302f27dadc28 · fixed in 7c099b0b292a68d0ef558527945dbfb756fbf893; From dd3c52846d5954acd43f0e771689302f27dadc28 · fixed in 7cc5ba756bc1cfffab9cb2695742f9f479dc73f7; From dd3c52846d5954acd43f0e771689302f27dadc28 · fixed in 35aa6730b8c5626b879a4e893fe664f59bf07d7f; From dd3c52846d5954acd43f0e771689302f27dadc28 · fixed in f296a0d5907bf88314dfda67245f7f69d1552470; From dd3c52846d5954acd43f0e771689302f27dadc28 · fixed in 5697d779577e2786ff3348ae9b77020ac0cf0aab; From dd3c52846d5954acd43f0e771689302f27dadc28 · fixed in aac3c5aababc7fb69d5bf5b0cc52d308574e3a8c; From dd3c52846d5954acd43f0e771689302f27dadc28 · fixed in e2bda39d7f9f285ec803e200b5c1f17143d0b483

  • Linux Linux

    5.12

  • KernelLinux

    From 5.12.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 7

git.kernel.org