Out-of-bounds Write Affecting linux-6.12 package, versions <6.12.100-1~deb12u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.13% (3rd percentile)

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  • Snyk IDSNYK-ECHOLATEST-LINUX612-18579247
  • published7 Aug 2026
  • disclosed25 Jul 2026

Introduced: 25 Jul 2026

CVE-2026-64402  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Echo:latest linux-6.12 to version 6.12.100-1~deb12u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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().

CVSS Base Scores

version 3.1