VulnerabilityPublished 18 Oct 2026Updated 21 Oct 2026

CVE-2026-98686: Linux kernel · smb: client: discard post-EOF pagecache when extending a file via zero range

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in da4fe97fb6c730d9c94a115c7bfa6f98e0d578d0 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:30 UTC

Severity

Unrated

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 da4fe97fb6c730d9c94a115c7bfa6f98e0d578d0, b75dadb50a25eed525264bf6fea44fad94e7626f, 94949b6b2f2bf0dba2e8786aed0b08cc6bc3a183 +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 ≥ 72c419d9b073628d3b5b0b2fc787b724f1a8c726, < da4fe97fb6c730d9c94a115c7bfa6f98e0d578d0	Fixed in da4fe97fb6c730d9c94a115c7bfa6f98e0d578d0
LinuxLinux	Affected ≥ 72c419d9b073628d3b5b0b2fc787b724f1a8c726, < b75dadb50a25eed525264bf6fea44fad94e7626f	Fixed in b75dadb50a25eed525264bf6fea44fad94e7626f
LinuxLinux	Affected ≥ 72c419d9b073628d3b5b0b2fc787b724f1a8c726, < 94949b6b2f2bf0dba2e8786aed0b08cc6bc3a183	Fixed in 94949b6b2f2bf0dba2e8786aed0b08cc6bc3a183
LinuxLinux	Affected ≥ 72c419d9b073628d3b5b0b2fc787b724f1a8c726, < 6a8279c98ad289b27c0bdb11adb3f0c0b7fd456d	Fixed in 6a8279c98ad289b27c0bdb11adb3f0c0b7fd456d
LinuxLinux	Affected ≥ 72c419d9b073628d3b5b0b2fc787b724f1a8c726, < 3df27277f8f95345d4a6c57367824bf1aefdbf66	Fixed in 3df27277f8f95345d4a6c57367824bf1aefdbf66
LinuxLinux	Affected =5.1	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: discard post-EOF pagecache when extending a file via zero range smb3_zero_range() removed the pagecache only for the range being zeroed, so when it extends the file the folio straddling the old EOF - which may hold data dirtied past EOF through an mmap - was never dropped and became visible as file content once the file was extended. Lower the discard boundary to the smaller of the zero-range offset and the old EOF.

References

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