VulnerabilityPublished 18 Oct 2026

CVE-2026-98684: Linux kernel · smb: client: flush and commit data before querying allocated ranges

Source GCVE Database

Authoritative record:CVE-2026-98684· High

Not known to be exploited · fixed in f82242fe3109a3ef72f429540b5bdde08fbfb0e4 : patch Linux kernel soon.

Data as of 26 Oct 2026, 12:55 UTC

Severity

High

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f82242fe3109a3ef72f429540b5bdde08fbfb0e4, bf84e44ff0ed802778eafd7ecb623635379cb506, aa994489bd835547c191827acc460192e147032d +3

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-6247-f99h-hr72

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=5.10.50 <5.11 >=5.12.17 <5.13 >=5.13.2 <5.14	Fixed in f82242fe3109a3ef72f429540b5bdde08fbfb0e4 bf84e44ff0ed802778eafd7ecb623635379cb506 aa994489bd835547c191827acc460192e147032d 5.14 5.13 5.11
LinuxLinux	Affected =5.14	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel that flushes dirty pages, drains outstanding I/O, and issues an SMB2 FLUSH before querying allocated ranges. Users should update to a Linux kernel version that includes this fix. No additional mitigation is required if the fix is applied.

Description

A vulnerability in the Linux kernel's SMB client implementation related to the handling of allocated ranges in the fallocate emulation was resolved. The issue arises because the FSCTL_QUERY_ALLOCATED_RANGES call on Windows servers may not reflect recently written data unless the data is flushed and committed first. This can lead to zero-filling of live data, causing data corruption. The fix ensures that dirty pages are written back, outstanding I/O is drained, and an SMB2 FLUSH is issued before querying allocated ranges, preventing data corruption.

Impact

Without the fix, the Linux kernel SMB client may corrupt data by zero-filling live data ranges after writes when interacting with Windows servers. This can lead to data loss or corruption on network file systems using SMB3 with fallocate emulation. The issue specifically affects interactions with Windows Server 2022 and similar SMB servers that do not guarantee coherency of FSCTL_QUERY_ALLOCATED_RANGES without flushing.

References

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