CVE-2026-89642: Linux kernel · cifs: call pagecache_isize_extended() in cifs_setsize() when extending
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 14:05 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 11 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 for this vulnerability has been implemented in the Linux kernel. Users should apply the official kernel updates that include this patch to ensure proper handling of pagecache extension in CIFS. Patch status is not explicitly confirmed in the provided data; therefore, check the vendor or distribution advisories for the exact fixed versions and remediation instructions.
Description
A vulnerability in the Linux kernel's CIFS implementation was resolved involving improper handling of pagecache extension during file size changes. The function cifs_setsize() failed to call pagecache_isize_extended() when extending the file size, which caused stale data to potentially be written back to the server in the newly extended file range. This issue was fixed by ensuring pagecache_isize_extended() is called appropriately to zero the tail of the page beyond the old end-of-file.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89642 (opens in a new tab)
- git.kernel.org/stable/c/12bafe32f09c0d24f5096154b59c347b9c6606e0 (opens in a new tab)
- git.kernel.org/stable/c/c510edb9734af1c274d18f4f31a471a166bbc7e8 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89642.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)
- ubuntu.com/security/CVE-2026-89642 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89642 (opens in a new tab)
- git.kernel.org/linus/c510edb9734af1c274d18f4f31a471a166bbc7e8 (opens in a new tab)