CVE-2025-39742: Debian Linux

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: RDMA: hfi1: fix possible divide-by-zero in find_hw_thread_mask() The function divides number of online CPUs by num_core_siblings, and later checks the divider by zero. This implies a possibility to get and divide-by-zero runtime error. Fix it by moving the check prior to division. This also helps to save one indentation level.

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 4.8, before 5.4.297 (fixed in 5.4.297); from 5.5, before 5.10.241 (fixed in 5.10.241); from 5.11, before 5.15.190 (fixed in 5.15.190); from 5.16, before 6.1.149 (fixed in 6.1.149); from 6.2, before 6.6.103 (fixed in 6.6.103); from 6.7, before 6.12.43 (fixed in 6.12.43); …

Published 2025-09-11. Last modified 2026-06-17.