Skip to content
Noroxi
NVD / CVE Program· CNA Linux

CVE-2025-38217: hwmon: (ftsteutates) Fix TOCTOU race in fts_read()

Noroxi assessment

Priority: Monitor (action score 18/100)

  • 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: 0.12% (FIRST EPSS).
  • 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.
  • Fixed version: Linux Linux 14c9ede9ca4cd078ad76a6ab9617b81074eb58bf, 4d646f627d3b7ed1cacca66e598af8bcd632d465, 83e2ba8971ccd8fc08319fc7593288f070d80a76; azl3 kernel 6.6.92.2-2 on Azure Linux 3.0 6.6.96.1-1.

Low priority for now. Upgrade to Linux Linux 14c9ede9ca4cd078ad76a6ab9617b81074eb58bf, 4d646f627d3b7ed1cacca66e598af8bcd632d465, 83e2ba8971ccd8fc08319fc7593288f070d80a76; azl3 kernel 6.6.92.2-2 on Azure Linux 3.0 6.6.96.1-1 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: hwmon: (ftsteutates) Fix TOCTOU race in fts_read() In the fts_read() function, when handling hwmon_pwm_auto_channels_temp, the code accesses the shared variable data->fan_source[channel] twice without holding any locks. It is first checked against FTS_FAN_SOURCE_INVALID, and if the check passes, it is read again when used as an argument to the BIT() macro. This creates a Time-of-Check to Time-of-Use (TOCTOU) race condition. Another thread executing fts_update_device() can modify the value of data->fan_source[channel] between the check and its use. If the value is changed to FTS_FAN_SOURCE_INVALID (0xff) during this window, the BIT() macro will be called with a large shift value (BIT(255)). A bit shift by a value greater than or equal to the type width is undefined behavior and can lead to a crash or incorrect values being returned to userspace. Fix this by reading data->fan_source[channel] into a local variable once, eliminating the race condition. Additionally, add a bounds check to ensure the value is less than BITS_PER_LONG before passing it to the BIT() macro, making the code more robust against undefined behavior. This possible bug was found by an experimental static analysis tool developed by our team.

MediumCVSS 4.7 · v3.1—No exploit Fix available
Published
Jul 4, 2025
Updated
Jun 17, 2026
EPSS
0.1% · 2th percentile

Report tools

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%

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-38217

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for linux records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

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.

We use this product, ask for help

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

Affected versions

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

  • linux linux kernel6.3 and later · before 6.6.95
  • linux linux kernel6.7 and later · before 6.12.35
  • linux linux kernel6.13 and later · before 6.15.4
  • linux linux kernel6.16

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

    • 6.3affected
    • 1c5759d8ce054961b454af69568a41e7e3210ee1 and later · before d95d87841d2a575bed3691884e8fedef57d7710daffected · git
    • 1c5759d8ce054961b454af69568a41e7e3210ee1 and later · before 83e2ba8971ccd8fc08319fc7593288f070d80a76affected · git
    • 1c5759d8ce054961b454af69568a41e7e3210ee1 and later · before 4d646f627d3b7ed1cacca66e598af8bcd632d465affected · git
    • 1c5759d8ce054961b454af69568a41e7e3210ee1 and later · before 14c9ede9ca4cd078ad76a6ab9617b81074eb58bfaffected · git
    • before 6.3not affected · semver
    • 6.6.95 and later · up to and including 6.6.*not affected · semver
    • 6.12.35 and later · up to and including 6.12.*not affected · semver
    • 6.15.4 and later · up to and including 6.15.*not affected · semver
    • 6.16 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.35-16.12.35-1

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-2025-38206Jul 4, 2025 · exfat: fix double free in delayed_free
    31Monitor
  • ← EarlierCVE-2025-38211Jul 4, 2025 · RDMA/iwcm: Fix use-after-free of work objects after cm_id destruction
    31Monitor
  • Later →CVE-2025-38218Jul 4, 2025 · f2fs: fix to do sanity check on sit_bitmap_size
    22Monitor

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 Linux14c9ede9ca4cd078ad76a6ab9617b81074eb58bfVendor (CNA)
Linux Linux4d646f627d3b7ed1cacca66e598af8bcd632d465Vendor (CNA)
Linux Linux83e2ba8971ccd8fc08319fc7593288f070d80a76Vendor (CNA)
Linux Linuxd95d87841d2a575bed3691884e8fedef57d7710dVendor (CNA)
azl3 kernel 6.6.92.2-2 on Azure Linux 3.06.6.96.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.12.35-1 · Debian:13Package 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-2025-3835218 days apartposix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()KEV
    61This week
  • CVE-2026-64091380 days apartbatman-adv: tt: fix TOCTOU race for reported vlans
    39Monitor
  • CVE-2026-64034380 days apartnet: mana: Fix TOCTOU double-fetch of hwc_msg_id from DMA buffer
    37Monitor
  • CVE-2026-63937380 days apartKVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer
    35Monitor
  • CVE-2026-63867380 days apartmptcp: close TOCTOU race while computing rcv_wnd
    32Monitor
  • CVE-2026-31678295 days apartopenvswitch: defer tunnel netdev_put to RCU release
    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

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (3 more)

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

All records