VulnerabilityPublished 6 Oct 2026Updated 21 Oct 2026

CVE-2026-98198: Linux kernel · hwmon: (pwm-fan) Stop RPM timer before freeing tach data

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in d073d306e587c1f35aaf9c07c42e54a3d5895d8f : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in d073d306e587c1f35aaf9c07c42e54a3d5895d8f, b48339b0a577783e4590a69e4cd2f2760ce33154, a5ce3fe5335a24d0220958c6866830a6d5fa1cc0 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 01695410d4529e38fea6159fa9f1260c598290b0, < d073d306e587c1f35aaf9c07c42e54a3d5895d8f	Fixed in d073d306e587c1f35aaf9c07c42e54a3d5895d8f
LinuxLinux	Affected ≥ 01695410d4529e38fea6159fa9f1260c598290b0, < b48339b0a577783e4590a69e4cd2f2760ce33154	Fixed in b48339b0a577783e4590a69e4cd2f2760ce33154
LinuxLinux	Affected ≥ 01695410d4529e38fea6159fa9f1260c598290b0, < a5ce3fe5335a24d0220958c6866830a6d5fa1cc0	Fixed in a5ce3fe5335a24d0220958c6866830a6d5fa1cc0
LinuxLinux	Affected ≥ 01695410d4529e38fea6159fa9f1260c598290b0, < 26d5ff79768548efb1e604bb6e8697c101e06269	Fixed in 26d5ff79768548efb1e604bb6e8697c101e06269
LinuxLinux	Affected ≥ 01695410d4529e38fea6159fa9f1260c598290b0, < 1e824fdb14a187ce56697e803b02b1e86243a755	Fixed in 1e824fdb14a187ce56697e803b02b1e86243a755
LinuxLinux	Affected =5.12	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: hwmon: (pwm-fan) Stop RPM timer before freeing tach data sample_timer() rearms the RPM timer and accesses the devm-managed ctx->tachs and ctx->pulses_per_revolution arrays. The cleanup action which stops the timer is registered before those arrays are allocated. Since devres releases entries in reverse order, driver detach can free the arrays before pwm_fan_cleanup() shuts down the timer. A timer expiry in that window accesses the freed tach data. With a KASAN kernel, a test-only kprobe delayed entry to pwm_fan_cleanup() while normal sysfs unbind ran. Each of three runs reported three four-byte reads and two four-byte writes in sample_timer() after its backing devm allocations had been freed. The helper did not invoke the timer callback, cleanup actions or free functions. With the fix, three matching unbind runs completed without KASAN, BUG, WARNING, Oops or panic. Instrumentation confirmed that timer retirement completed before the first timer backing allocation was released. Split timer retirement from the power cleanup and register its devres action after the timer backing data and IRQ actions are installed. This preserves the early power rollback action while ensuring the timer is retired before its backing data is released. Use timer_shutdown_sync() because the callback can rearm itself.

References

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