CVE-2025-39742 | RDMA: hfi1: fix possible divide-by-zero in find_hw_thread_mask()

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.

Published: 2025-09-11 Last update: 2026-05-12 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-39742 is rated Low Risk (24.8/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.03%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-39742

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-09-12 — 0.03% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-39742

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]

Weakness enumeration for CVE-2025-39742

GitHub Security Advisory for CVE-2025-39742

GHSA-3xq3-w9mf-92jr · Severity: medium — In the Linux kernel, the following vulnerability has been resolved: RDMA: hfi1: fix possible...

OS Trackers for CVE-2025-39742

vendor priority summary link
debian not yet assigned CVE-2025-39742 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2025-39742
redhat medium — https://access.redhat.com/security/cve/CVE-2025-39742
suse high — https://www.suse.com/security/cve/CVE-2025-39742/
ubuntu medium CVE-2025-39742 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1414 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1017, ignored 180, released 150, needed 48, not-affected 16, needs-triage 2, pending 1. https://ubuntu.com/security/CVE-2025-39742

Affected software / configurations for CVE-2025-39742

Vendor Product Version Raw CPE
linux linux_kernel >= 4.8, < 5.4.297 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.5, < 5.10.241 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.11, < 5.15.190 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.16, < 6.1.149 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.2, < 6.6.103 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.7, < 6.12.43 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.15.11 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.16, < 6.16.2 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2025-39742

URL Tags
https://git.kernel.org/stable/c/1a7cf828ed861de5be1aff99e10f114b363c19d3 Patch
https://git.kernel.org/stable/c/31d0599a23efdbfe579bfbd1eb8f8c942f13744d Patch
https://git.kernel.org/stable/c/4b4317b0d758ff92ba96f4e448a8992a6fe607bf Patch
https://git.kernel.org/stable/c/59f7d2138591ef8f0e4e4ab5f1ab674e8181ad3a Patch
https://git.kernel.org/stable/c/89fdac333a17ed990b41565630ef4791782e02f5 Patch
https://git.kernel.org/stable/c/9b05e91afe948ed819bf87d7ba0fccf451ed79a6 Patch
https://git.kernel.org/stable/c/9bba1a9994c523b44db64f63b564b4719ea2b7ef Patch
https://git.kernel.org/stable/c/9d3211cb61a0773a2440d0a0698c1e6e7429f907 Patch
https://git.kernel.org/stable/c/ac53f377393cc85156afdc90b636e84e544a6f96 Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html Mailing List Third Party Advisory
https://cert-portal.siemens.com/productcert/html/ssa-032379.html
cvelogic Threat Intelligence