In the Linux kernel, the following vulnerability has been resolved: NFS: Return a delegation the client fails to record When an NFS server grants a… (CVE-2026-90234)
A vulnerability in the Linux kernel's NFS implementation causes the client to fail to record certain delegations granted by the server. This occurs because some error flows in nfs_inode_set_delegation() return without sending the required DELEGRETURN message, leaving the server with an incorrect belief that the client still holds the delegation. This results in the client responding with errors during delegation recall and causes the client's state manager to loop indefinitely. The issue is triggered by a race condition involving write delegations on OPEN operations.
AI Analysis
Technical Summary
The Linux kernel NFS vulnerability (CVE-2026-90234) involves improper handling of delegation returns. When an NFS server grants a delegation in an OPEN reply, the client is supposed to record it and send a DELEGRETURN message upon relinquishment. However, three error paths in nfs_inode_set_delegation() fail to send DELEGRETURN, causing the server to mistakenly believe the client still holds the delegation. This leads to the client responding with NFS4ERR_BADHANDLE during delegation recall, the server revoking the delegation and marking it as revoked, and the client entering a loop issuing TEST_STATEID calls without clearing the revoked state. The vulnerability is easily triggered by a race condition when a server offers write delegations on write OPEN calls.
Potential Impact
The vulnerability causes denial of service conditions on the client side due to the client's state manager entering an indefinite loop handling revoked delegations. This can degrade NFS client performance and reliability. There is no confidentiality or integrity impact reported. No known exploits in the wild have been identified.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, monitoring for symptoms related to delegation recall errors and avoiding workloads that trigger frequent delegation recalls may reduce impact. Follow official Linux kernel updates for patches addressing this issue.
In the Linux kernel, the following vulnerability has been resolved: NFS: Return a delegation the client fails to record When an NFS server grants a… (CVE-2026-90234)
Description
A vulnerability in the Linux kernel's NFS implementation causes the client to fail to record certain delegations granted by the server. This occurs because some error flows in nfs_inode_set_delegation() return without sending the required DELEGRETURN message, leaving the server with an incorrect belief that the client still holds the delegation. This results in the client responding with errors during delegation recall and causes the client's state manager to loop indefinitely. The issue is triggered by a race condition involving write delegations on OPEN operations.
CVSS v3.1
Score 7.5high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel NFS vulnerability (CVE-2026-90234) involves improper handling of delegation returns. When an NFS server grants a delegation in an OPEN reply, the client is supposed to record it and send a DELEGRETURN message upon relinquishment. However, three error paths in nfs_inode_set_delegation() fail to send DELEGRETURN, causing the server to mistakenly believe the client still holds the delegation. This leads to the client responding with NFS4ERR_BADHANDLE during delegation recall, the server revoking the delegation and marking it as revoked, and the client entering a loop issuing TEST_STATEID calls without clearing the revoked state. The vulnerability is easily triggered by a race condition when a server offers write delegations on write OPEN calls.
Potential Impact
The vulnerability causes denial of service conditions on the client side due to the client's state manager entering an indefinite loop handling revoked delegations. This can degrade NFS client performance and reliability. There is no confidentiality or integrity impact reported. No known exploits in the wild have been identified.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, monitoring for symptoms related to delegation recall errors and avoiding workloads that trigger frequent delegation recalls may reduce impact. Follow official Linux kernel updates for patches addressing this issue.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-qx9f-2gch-8fvp
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-90234"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6aade52155bf5e2cf5edc180
Added to database: 09/19/2026, 01:28:01 UTC
Last enriched: 09/19/2026, 01:50:09 UTC
Last updated: 09/19/2026, 04:02:33 UTC
Views: 3
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