smb: client: reject userspace cifs.idmap descriptions
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 5 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: reject userspace cifs.idmap descriptions cifs.idmap key descriptions carry authority-bearing fields (owner and group SIDs and uid/gid values in "os:"/"gs:"/"oi:"/"gi:" form) that the cifs.idmap upcall helper treats as kernel-originating inputs. Unlike its sibling cifs.spnego, the cifs.idmap key type has no vet_description hook, so userspace can create keys of this type through request_key(2)/add_key(2) and supply those fields without CIFS origin. A request_key(2) call with a non-NULL callout then drives a root usermodehelper upcall (/sbin/request-key -> cifs.idmap) that consumes the unvetted description in root context. Only accept cifs.idmap descriptions while CIFS is using its private root_cred to request the key. id_to_sid()/sid_to_id() already run under override_creds(root_cred), so the kernel-originated path is unaffected. This mirrors commit 3da1fdf4efbc ("smb: client: reject userspace cifs.spnego descriptions"), which applied the same restriction to cifs.spnego.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.7, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-97564
- 2026-10-03 Alias added: GHSA-3fc8-28wq-wq67
- 2026-10-03 Fix available: Linux/Linux@17c93bcd17755523c21abb22cbf2a41a6eb0caaf, Linux/[email protected], Linux/[email protected] +1 · CNA
- 2026-10-03 2 new references · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-30 Affected versions changed · Red Hat
- 2026-10-30 Fix available: Linux/[email protected], Linux/[email protected], Linux/Linux@856cb3f05b49d23dc1542f78696e20c4ea6dd7de +1 · CNA
- 2026-10-30 2 new references · CNA
References
Other 8
- https://git.kernel.org/stable/c/91da70a2e5c6f54e1316d51e0e6911e78ef5e09a
- https://git.kernel.org/stable/c/856cb3f05b49d23dc1542f78696e20c4ea6dd7de
- https://git.kernel.org/stable/c/f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a
- https://git.kernel.org/stable/c/17c93bcd17755523c21abb22cbf2a41a6eb0caaf
- https://git.kernel.org/stable/c/e5964064e3fbe6325893408faff08ca33de0e2c3
- https://git.kernel.org/stable/c/96751028c0d4dec785709ea3eb0ab38a4f2ded96
- https://git.kernel.org/stable/c/1d3b24b16a0b013792e8f1e3ed060f0b46f537d1
- https://git.kernel.org/stable/c/d9d7eeb0cea5b55b82888f443622fd8d4ee064f3
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Sources
- CVE-2026-97564 · CVE Program
- CVE-2026-97564 · NVD
- FIRST EPSS
- GHSA-3fc8-28wq-wq67 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-97564 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences