Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-07-25T00:00:00 kernel: coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer() 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CWE-787

In the Linux kernel, the following vulnerability has been resolved: coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer() When the SMB sink is used as a perf AUX sink, smb_update_buffer() calls smb_sync_perf_buffer() to copy hardware trace data into the perf AUX ring buffer pages. It derives pg_idx = head >> PAGE_SHIFT from @head, which is handle->head, and indexes dst_pages[pg_idx]. The pg_idx %= nr_pages normalization is only applied after the first loop iteration. This leaves the initial page index underived from the buffer size, which can result in an out-of-bounds write past dst_pages[] when head exceeds the AUX buffer size. Normalize head modulo the AUX buffer size before deriving the page index and offset, mirroring tmc_etr_sync_perf_buffer().

A flaw was found in the Linux kernel's coresight ultrasoc-smb component. This vulnerability involves an out-of-bounds write in the `smb_sync_perf_buffer()` function. An attacker could potentially exploit this by causing the system to write data beyond the intended memory buffer, which may lead to system instability or a denial of service (DoS). This occurs because a page index is calculated incorrectly before being properly normalized, allowing the system to access memory outside its allocated boundaries.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64402 https://nvd.nist.gov/vuln/detail/CVE-2026-64402 https://lore.kernel.org/linux-cve-announce/2026072530-CVE-2026-64402-af30@gregkh/T