| Release Date: | 2025-12-08 | |
| Impact: | Important | What is this? |
In the Linux kernel, the following vulnerability has been resolved: NFSD: Define actions for the new time_deleg FATTR4 attributes NFSv4 clients won't send legitimate GETATTR requests for these new attributes because they are intended to be used only with CB_GETATTR and SETATTR. But NFSD has to do something besides crashing if it ever sees a GETATTR request that queries these attributes. RFC 8881 Section 18.7.3 states: > The server MUST return a value for each attribute that the client > requests if the attribute is supported by the server for the > target file system. If the server does not support a particular > attribute on the target file system, then it MUST NOT return the > attribute value and MUST NOT set the attribute bit in the result > bitmap. The server MUST return an error if it supports an > attribute on the target but cannot obtain its value. In that case, > no attribute values will be returned. Further, RFC 9754 Section 5 states: > These new attributes are invalid to be used with GETATTR, VERIFY, > and NVERIFY, and they can only be used with CB_GETATTR and SETATTR > by a client holding an appropriate delegation. Thus there does not appear to be a specific server response mandated by specification. Taking the guidance that querying these attributes via GETATTR is "invalid", NFSD will return nfserr_inval, failing the request entirely.
See more information about CVE-2025-40326 from MITRE CVE dictionary and NIST NVD
NOTE: The following CVSS metrics and score provided are preliminary and subject to review.
| Base Score: | 7.5 |
| Vector String: | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Version: | 3.1 |
| Attack Vector: | Network |
| Attack Complexity: | Low |
| Privileges Required: | None |
| User Interaction: | None |
| Scope: | Unchanged |
| Confidentiality Impact: | None |
| Integrity Impact: | None |
| Availability Impact: | High |
| Platform | Errata | Release Date |
| Oracle Linux version 10 (kernel-uek) | ELSA-2026-500572 | 2026-11-02 |
| Oracle Linux version 9 (kernel-uek) | ELSA-2026-500572 | 2026-11-02 |
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