CVE Catalog

CVE-2025-40326

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.31%

24th percentile - higher than 24% of all known CVEs

Summary

In the Linux kernel, NFSD lacks handling for the new time_deleg FATTR4 attributes in GETATTR requests. The server may crash if a client sends an invalid GETATTR for these attributes. According to RFC specification, such usage is invalid, and NFSD will return nfserr_inval.

Risk Assessment

Risk of NFS server crash when a client sends an invalid GETATTR request for the new attributes. This could lead to service disruption and potential DoS attack.

Recommendation

Apply the Linux kernel patch that adds proper handling for these attributes. Update the system to a kernel version containing the fix.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS