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CVE-2025-71111· NVD / CVE Program· CNA Linux

hwmon: (w83791d) Convert macros to functions to avoid TOCTOU

In the Linux kernel, the following vulnerability has been resolved: hwmon: (w83791d) Convert macros to functions to avoid TOCTOU The macro FAN_FROM_REG evaluates its arguments multiple times. When used in lockless contexts involving shared driver data, this leads to Time-of-Check to Time-of-Use (TOCTOU) race conditions, potentially causing divide-by-zero errors. Convert the macro to a static function. This guarantees that arguments are evaluated only once (pass-by-value), preventing the race conditions. Additionally, in store_fan_div, move the calculation of the minimum limit inside the update lock. This ensures that the read-modify-write sequence operates on consistent data. Adhere to the principle of minimal changes by only converting macros that evaluate arguments multiple times and are used in lockless contexts.

MediumCVSS 4.7 · v3.1—No exploit Fix available
Published
Jan 14, 2026
Updated
Jun 17, 2026
EPSS
0.1% · 1th percentile
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JSON

Action score

18

Monitor

Low priority for now.

CVSS
18 / 40 · 4.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Affected systems

VendorProduct
linuxlinux kernel

Affected versions

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

  • linux linux kernel2.6.18.1 and later · before 5.10.248
  • linux linux kernel5.11 and later · before 5.15.198
  • linux linux kernel5.16 and later · before 6.1.160
  • linux linux kernel6.2 and later · before 6.6.120
  • linux linux kernel6.7 and later · before 6.12.64
  • linux linux kernel6.13 and later · before 6.18.3
  • linux linux kernel2.6.18
  • linux linux kernel6.19

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

    • 2.6.18affected
    • 9873964d6eb24bd0205394f9b791de9eddbcb855 and later · before 3dceb68f6ad33156032ef4da21a93d84059cca6daffected · git
    • 9873964d6eb24bd0205394f9b791de9eddbcb855 and later · before bf5b03227f2e6d4360004886d268f9df8993ef8faffected · git
    • 9873964d6eb24bd0205394f9b791de9eddbcb855 and later · before f2b579a0c37c0df19603d719894a942a295f634aaffected · git
    • 9873964d6eb24bd0205394f9b791de9eddbcb855 and later · before f94800fbc26ccf7c81eb791707b038a57aa39a18affected · git
    • 9873964d6eb24bd0205394f9b791de9eddbcb855 and later · before a9fb6e8835a22f5796c1182ed612daed3fd273afaffected · git
    • 9873964d6eb24bd0205394f9b791de9eddbcb855 and later · before c8cf0c2bdcccc6634b6915ff793b844e12436680affected · git
    • 9873964d6eb24bd0205394f9b791de9eddbcb855 and later · before 670d7ef945d3a84683594429aea6ab2cdfa5ceb4affected · git
    • before 2.6.18not affected · semver
    • 5.10.248 and later · up to and including 5.10.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.162-16.1.162-1
Debian:13linuxbefore 6.12.69-16.12.69-1
Debian:14linuxbefore 6.18.3-16.18.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now
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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 Linux3dceb68f6ad33156032ef4da21a93d84059cca6dVendor (CNA)
Linux Linux670d7ef945d3a84683594429aea6ab2cdfa5ceb4Vendor (CNA)
Linux Linuxa9fb6e8835a22f5796c1182ed612daed3fd273afVendor (CNA)
Linux Linuxbf5b03227f2e6d4360004886d268f9df8993ef8fVendor (CNA)
Linux Linuxc8cf0c2bdcccc6634b6915ff793b844e12436680Vendor (CNA)
Linux Linuxf2b579a0c37c0df19603d719894a942a295f634aVendor (CNA)
Linux Linuxf94800fbc26ccf7c81eb791707b038a57aa39a18Vendor (CNA)
debian:linux6.1.162-1 · Debian:12Package 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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-2025-38352176 days apartposix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()KEV
    61This week
  • CVE-2026-64091186 days apartbatman-adv: tt: fix TOCTOU race for reported vlans
    39Monitor
  • CVE-2026-31678101 days apartopenvswitch: defer tunnel netdev_put to RCU release
    31Monitor
  • CVE-2026-43433114 days apartrust_binder: avoid reading the written value in offsets array
    31Monitor
  • CVE-2026-53145162 days apartdrm/gem: Try to fix change_handle ioctl, attempt 4
    31Monitor
  • CVE-2026-53250162 days apartxsk: cache csum_start/csum_offset to fix TOCTOU in xsk_skb_metadata()
    31Monitor

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.
  • Special conditions such as timing or configuration are required.

If successful

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

Weakness class (CWE)

CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition

CVSS vector

CVSS:3.1/AV:L/AC:H/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.

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

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Change log

  1. Fix✗ → ✓

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

References

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

All records