CVE-2026-97564: Linux kernel · smb: client: reject userspace cifs.idmap descriptions
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 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 25 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 has been implemented in the Linux kernel to restrict acceptance of cifs.idmap descriptions to only when CIFS uses its private root credentials. Users should update to a Linux kernel version that includes this fix. Patch status is not explicitly stated in the provided data; therefore, check the vendor advisory for the current remediation guidance.
Description
A vulnerability in the Linux kernel's SMB client component allowed userspace to create cifs.idmap keys with authority-bearing fields that were treated as kernel-originating inputs. This could lead to unvetted descriptions being consumed in root context. The issue was resolved by restricting acceptance of cifs.idmap descriptions to only when CIFS uses its private root credentials to request the key, mirroring a similar fix for cifs.spnego.
References
- ubuntu.com/security/CVE-2026-97564 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-97564 (opens in a new tab)
- git.kernel.org/stable/c/1d3b24b16a0b013792e8f1e3ed060f0b46f537d1 (opens in a new tab)
- git.kernel.org/stable/c/d9d7eeb0cea5b55b82888f443622fd8d4ee064f3 (opens in a new tab)
- git.kernel.org/stable/c/e5964064e3fbe6325893408faff08ca33de0e2c3 (opens in a new tab)
- git.kernel.org/stable/c/96751028c0d4dec785709ea3eb0ab38a4f2ded96 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-97564 (opens in a new tab)
- git.kernel.org/stable/c/17c93bcd17755523c21abb22cbf2a41a6eb0caaf (opens in a new tab)
- git.kernel.org/stable/c/f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a (opens in a new tab)