CVE-2026-93794: Linux kernel · smb/client: flush dirty data before punching a hole
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 13:47 UTC
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.
Exploitation evidence
Disclosed: evidence found.
CVE published 24 Sep 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.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available that flushes dirty data before punching a hole in the file, preventing the hole from being refilled incorrectly. Users should apply the updated Linux kernel versions that include this fix. Since this is a kernel-level fix, upgrading to a patched kernel version is the recommended remediation.
Description
A vulnerability in the Linux kernel's SMB client implementation could cause file hole punching operations to incorrectly report data ranges. Specifically, punching a hole after a large buffered write may leave the range reported as data instead of a hole, due to dirty data being written back after the punch operation. This issue has been resolved by flushing dirty data before invalidating the page cache and issuing the FSCTL_SET_ZERO_DATA command.
References
- ubuntu.com/security/CVE-2026-93794 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-93794 (opens in a new tab)
- git.kernel.org/stable/c/d7d2adcd022baade5cab65ca492ce63421ce3a6e (opens in a new tab)
- git.kernel.org/stable/c/6c265aca08155e519a8f6f6071c59dff4f535f70 (opens in a new tab)
- git.kernel.org/stable/c/39562a56cdb515f6635c3e7bfe6629439b18a169 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-93794 (opens in a new tab)
- git.kernel.org/stable/c/216e469586057c29409e4ef8311d282388c6e251 (opens in a new tab)