Summary
In the Linux kernel, the following vulnerability has been resolved: NFSD: Define actions for the...
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.
Impact
CVE-2025-40326 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-40326? CVE-2025-40326 is a high-severity security vulnerability. No fixed version is listed yet.
- How severe is CVE-2025-40326? CVE-2025-40326 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-40326? No fixed version is listed for CVE-2025-40326 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-40326 exploitable, and should I be worried? Whether CVE-2025-40326 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-40326 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.