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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 1a7cf828ed861de5be1aff99e10f114b363c19d3, 31d0599a23efdbfe579bfbd1eb8f8c942f13744d, 4b4317b0d758ff92ba96f4e448a8992a6fe607bf.

Low priority for now. Upgrade to Linux Linux 1a7cf828ed861de5be1aff99e10f114b363c19d3, 31d0599a23efdbfe579bfbd1eb8f8c942f13744d, 4b4317b0d758ff92ba96f4e448a8992a6fe607bf or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Sep 11, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 7th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux11.0
  • linux linux kernel5.5 and later · before 5.10.241
  • linux linux kernel5.11 and later · before 5.15.190
  • linux linux kernel5.16 and later · before 6.1.149
  • linux linux kernel4.8 and later · before 5.4.297
  • linux linux kernel6.7 and later · before 6.12.43
  • linux linux kernel6.13 and later · before 6.15.11
  • linux linux kernel6.16 and later · before 6.16.2
  • linux linux kernel6.2 and later · before 6.6.103

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.8affected
    • b094a36f90975373c3a241839869217a65f17d81 and later · before 9bba1a9994c523b44db64f63b564b4719ea2b7efaffected · git
    • b094a36f90975373c3a241839869217a65f17d81 and later · before 1a7cf828ed861de5be1aff99e10f114b363c19d3affected · git
    • b094a36f90975373c3a241839869217a65f17d81 and later · before 9d3211cb61a0773a2440d0a0698c1e6e7429f907affected · git
    • b094a36f90975373c3a241839869217a65f17d81 and later · before 4b4317b0d758ff92ba96f4e448a8992a6fe607bfaffected · git
    • b094a36f90975373c3a241839869217a65f17d81 and later · before 89fdac333a17ed990b41565630ef4791782e02f5affected · git
    • b094a36f90975373c3a241839869217a65f17d81 and later · before 9b05e91afe948ed819bf87d7ba0fccf451ed79a6affected · git
    • b094a36f90975373c3a241839869217a65f17d81 and later · before 31d0599a23efdbfe579bfbd1eb8f8c942f13744daffected · git
    • b094a36f90975373c3a241839869217a65f17d81 and later · before ac53f377393cc85156afdc90b636e84e544a6f96affected · git
    • b094a36f90975373c3a241839869217a65f17d81 and later · before 59f7d2138591ef8f0e4e4ab5f1ab674e8181ad3aaffected · git

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.153-16.1.153-1
Debian:13linuxbefore 6.12.43-16.12.43-1
Debian:14linuxbefore 6.16.3-16.16.3-1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_35before 19-150400.2.119-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_36before 14-150400.2.114-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_40before 13-150400.2.113-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_44before 7-150400.2.17-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_45before 5-150400.2.15-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_24before 14-150500.2.114-150500.2.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_26before 13-150500.2.113-150500.2.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_28before 11-150500.2.111-150500.2.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_30before 6-150500.2.16-150500.2.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_31before 4-150500.2.14-150500.2.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_10before 12-150600.2.112-150600.2.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_13before 10-150600.2.110-150600.2.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_14before 6-150600.2.16-150600.2.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_7before 18-150600.2.118-150600.2.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_8before 13-150600.2.113-150600.2.1
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7_Update_0before 10-150700.3.27.110-150700.3.27.1
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7_Update_1before 10-150700.2.110-150700.2.1
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7_Update_2before 10-150700.2.110-150700.2.1
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7_Update_3before 6-150700.2.16-150700.2.1
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7-RT_Update_1before 10-150700.2.110-150700.2.1
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7-RT_Update_2before 10-150700.2.110-150700.2.1

+17

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-39740Sep 11, 2025 · drm/xe/migrate: prevent potential UAF
    31Monitor
  • ← EarlierCVE-2025-39741Sep 11, 2025 · drm/xe/migrate: don't overflow max copy size
    22Monitor
  • Later →CVE-2025-39743Sep 11, 2025 · jfs: truncate good inode pages when hard link is 0
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux1a7cf828ed861de5be1aff99e10f114b363c19d3Vendor (CNA)
Linux Linux31d0599a23efdbfe579bfbd1eb8f8c942f13744dVendor (CNA)
Linux Linux4b4317b0d758ff92ba96f4e448a8992a6fe607bfVendor (CNA)
Linux Linux59f7d2138591ef8f0e4e4ab5f1ab674e8181ad3aVendor (CNA)
Linux Linux89fdac333a17ed990b41565630ef4791782e02f5Vendor (CNA)
Linux Linux9b05e91afe948ed819bf87d7ba0fccf451ed79a6Vendor (CNA)
Linux Linux9bba1a9994c523b44db64f63b564b4719ea2b7efVendor (CNA)
Linux Linux9d3211cb61a0773a2440d0a0698c1e6e7429f907Vendor (CNA)
Linux Linuxac53f377393cc85156afdc90b636e84e544a6f96Vendor (CNA)
debian:linux6.1.153-1 · Debian:12Package registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_3519-150400.2.1 · SUSE:Linux Enterprise Live Patching 15 SP4Package registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_4013-150400.2.1 · SUSE:Linux Enterprise Live Patching 15 SP4Package registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_455-150400.2.1 · SUSE:Linux Enterprise Live Patching 15 SP4Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5_Update_2414-150500.2.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5_Update_2613-150500.2.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5_Update_2811-150500.2.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5_Update_306-150500.2.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5_Update_314-150500.2.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6_Update_718-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP7-RT_Update_110-150700.2.1 · SUSE:Linux Enterprise Live Patching 15 SP7Package registry (OSV)
suse:kernel-livepatch-SLE15-SP7-RT_Update_210-150700.2.1 · SUSE:Linux Enterprise Live Patching 15 SP7Package registry (OSV)
suse:kernel-livepatch-SLE15-SP7-RT_Update_36-150700.2.1 · SUSE:Linux Enterprise Live Patching 15 SP7Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2024-26945498 days apartcrypto: iaa - Fix nr_cpus < nr_iaa case
    33Monitor
  • CVE-2025-387197 days apartnet: hibmcge: fix the division by zero issue
    22Monitor
  • CVE-2025-3990920 days apartmm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters()
    22Monitor
  • CVE-2025-3991620 days apartmm/damon/reclaim: avoid divide-by-zero in damon_reclaim_apply_parameters()
    22Monitor
  • CVE-2025-3851926 days apartmm/damon: fix divide by zero in damon_get_intervals_score()
    22Monitor
  • CVE-2025-3995428 days apartclk: sunxi-ng: mp: Fix dual-divider clock rate readback
    22Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-369 · Divide By Zero

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (11 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records