VulnerabilityPublished 18 Oct 2026

CVE-2026-98635: Linux kernel · scsi: block: Fix zones_cond out-of-bounds write on zone report

Source GCVE Database

Authoritative record:CVE-2026-98635· High

Not known to be exploited : upgrade to ca688bb207957cffa5a8cad207329b0dcac1f2c0 or 7c431d61b69a3fd0784c20aa4cd0b8fb501b5653 soon.

Data as of 26 Oct 2026, 17:16 UTC

Severity

High

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 ca688bb207957cffa5a8cad207329b0dcac1f2c0, 7c431d61b69a3fd0784c20aa4cd0b8fb501b5653

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.

ghsa-xmm2-hmmq-mgf4

What to do

Upgrade Linux kernel to ca688bb207957cffa5a8cad207329b0dcac1f2c0 or 7c431d61b69a3fd0784c20aa4cd0b8fb501b5653.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 6e945ffb6555705cf20b1fcdc21a139911562995, < ca688bb207957cffa5a8cad207329b0dcac1f2c0	Fixed in ca688bb207957cffa5a8cad207329b0dcac1f2c0
LinuxLinux	Affected ≥ 6e945ffb6555705cf20b1fcdc21a139911562995, < 7c431d61b69a3fd0784c20aa4cd0b8fb501b5653	Fixed in 7c431d61b69a3fd0784c20aa4cd0b8fb501b5653
LinuxLinux	Affected =6.19	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel to check zone indices against the array size and to refuse revalidation when the zone count exceeds 32 bits. Users should update to a kernel version that includes this fix once available.

Description

A vulnerability in the Linux kernel's SCSI block subsystem allowed an out-of-bounds write due to improper bounds checking on zone report data. The issue occurred when a device reported more zones than the allocated array size, particularly when the zone count exceeded 32 bits, causing array undersizing and potential memory corruption. The flaw was fixed by adding index bounds checking and refusing to revalidate when the zone count does not fit in 32 bits.

Impact

This vulnerability could lead to out-of-bounds memory writes in the kernel, potentially causing memory corruption, system instability, or crashes. However, exploitation requires a device reporting an abnormally large number of zones exceeding 32 bits, which is an unusual scenario. There are no known exploits in the wild.

Summary

The vulnerability in the Linux kernel's SCSI block layer involved the function blk_revalidate_disk_zones() sizing the zones_cond array based on disk capacity and zone size, but the index used by blk_revalidate_zone_cond() was derived from the device's report_zones() walk without bounds checking. If a device reported more zones than the array could hold, especially when the zone count exceeded UINT_MAX (32-bit unsigned int), the zone count was truncated, leading to an undersized array and out-of-bounds writes by blk_zone_set_cond(). The fix involved checking the index against the array size before writing and refusing to revalidate if the zone count exceeds 32 bits.

References

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