VulnerabilityPublished 18 Oct 2026Updated 21 Oct 2026

CVE-2026-98848: Linux kernel · rtc: ac100: Assign .num before accessing .hws

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in e77c5fc1f39fdb06ecd1f55b101eea1e1db2ffef : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in e77c5fc1f39fdb06ecd1f55b101eea1e1db2ffef, ad1bf77039cba83373bf1eff3784655e3e3ed2ab, 160619b38707241e22569f9c983a4b3d0890996a +2

Exploitation evidence

Disclosed: evidence found.
CVE published 18 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 ≥ f316cdff8d677db9ad9c90acb44c4cd535b0ee27, < e77c5fc1f39fdb06ecd1f55b101eea1e1db2ffef	Fixed in e77c5fc1f39fdb06ecd1f55b101eea1e1db2ffef
LinuxLinux	Affected ≥ f316cdff8d677db9ad9c90acb44c4cd535b0ee27, < ad1bf77039cba83373bf1eff3784655e3e3ed2ab	Fixed in ad1bf77039cba83373bf1eff3784655e3e3ed2ab
LinuxLinux	Affected ≥ f316cdff8d677db9ad9c90acb44c4cd535b0ee27, < 160619b38707241e22569f9c983a4b3d0890996a	Fixed in 160619b38707241e22569f9c983a4b3d0890996a
LinuxLinux	Affected ≥ f316cdff8d677db9ad9c90acb44c4cd535b0ee27, < 6bb55381daf1a1bed0657189a1396e7467712525	Fixed in 6bb55381daf1a1bed0657189a1396e7467712525
LinuxLinux	Affected ≥ f316cdff8d677db9ad9c90acb44c4cd535b0ee27, < 6a4117eee82dd85f11bf898bf66026764011eeb6	Fixed in 6a4117eee82dd85f11bf898bf66026764011eeb6
LinuxLinux	Affected =6.6	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: rtc: ac100: Assign .num before accessing .hws Commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by") annotated the hws member of 'struct clk_hw_onecell_data' with __counted_by, which informs the bounds sanitizer (UBSAN_BOUNDS) about the number of elements in .hws[], so that it can warn when .hws[] is accessed out of bounds. As noted in that change, the __counted_by member must be initialized with the number of elements before the first array access happens, otherwise there will be a warning from each access prior to the initialization because the number of elements is zero. This occurs in ac100_rtc_register_clks() due to .num being assigned only after every clkout clock has been stored in .hws[]. With CONFIG_UBSAN_BOUNDS and a compiler that implements __counted_by (GCC 15.1+ or Clang 20.1+), this triggers an array-index-out-of-bounds report during probe, and with CONFIG_UBSAN_TRAP the first store traps. Initialize .num with AC100_CLKOUT_NUM, the number of elements .hws[] was allocated with, right after the allocation. That is the value the loop counter ends up at on the success path anyway, so the provider's behaviour is unchanged.

References

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