Security readout for executives and security teams
Plain-English summary
A flaw in the Linux kernel NFS server can leak kernel memory when an NFS delegation-recall task cannot be queued. Repeated failures could consume resources and disrupt availability. The supplied CVSS score is 7.5, but the sources provide no evidence of data theft, modification, or active exploitation.
Executive priority
Prioritize externally reachable or business-critical NFS servers for prompt vendor-supported kernel updates. The expected impact is service degradation or outage rather than confidentiality loss. Avoid declaring an emergency solely from the score because active exploitation and reliable triggering are not demonstrated.
Technical view
The NFS server increments the dl_stid reference count before queuing dl_recall work. If nfsd4_run_cb fails, the callback that normally releases the reference never runs, leaving an nfs4_stid allocation leaked. The documented fix checks the queueing result and calls nfs4_put_stid on failure.
Likely exposure
Exposure is concentrated on systems running affected Linux kernels with the kernel NFS server active. Network-accessible NFS servers warrant priority. Systems not providing NFS service are unlikely to reach this code path. The supplied version data is ambiguous, so confirm affected and fixed packages with each distribution vendor.
Exploitation context
The CVSS vector characterizes the issue as remotely reachable, low complexity, unauthenticated, and availability-only. However, the bundle contains no proof-of-concept, reported attacks, or CISA KEV listing. Whether an attacker can reliably force the required callback-queue failure is not established by the supplied evidence.
Researcher notes
The failure is a reference-count leak in the delegation-recall callback error path, supported by kernel leak traces. The stable commits show a narrowly scoped release-on-queue-failure correction. No CWE was supplied. Exact vulnerable ranges, practical trigger reliability, and exploit prevalence remain insufficiently documented in the bundle.
Mitigation direction
- Inventory Linux systems providing kernel NFS service and record their running kernel packages.
- Apply a distribution-supported kernel update containing the documented NFS reference-release fix.
- Consult distribution advisories for exact fixed package versions and backport status.
- Reboot affected systems when required so the corrected kernel is actually running.
- If updates are delayed, follow vendor guidance and limit NFS access to necessary trusted clients.
Validation and detection
- Confirm whether the kernel NFS server is enabled and serving network clients.
- Compare each running kernel package against the relevant distribution security advisory.
- Verify the installed kernel includes the nfsd4_run_cb failure-path reference-release fix.
- Confirm the corrected kernel is running after maintenance or reboot.
- Review monitoring for unexplained nfsd-related memory growth or resource exhaustion.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CVE-2025-22025 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6LinuxVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/b874cdef4e67e5150e07eff0eae1cbb21fb92da1CVE reference, Linux
- https://git.kernel.org/stable/c/cdb796137c57e68ca34518d53be53b679351eb86CVE reference, Linux
- https://git.kernel.org/stable/c/d96587cc93ec369031bcd7658c6adc719873c9fdCVE reference, Linux
- https://git.kernel.org/stable/c/9a81cde8c7ce65dd90fb47ceea93a45fc1a2fbd1CVE reference, Linux
- https://git.kernel.org/stable/c/cad3479b63661a399c9df1d0b759e1806e2df3c8CVE reference, Linux
- https://git.kernel.org/stable/c/63b91c8ff4589f5263873b24c052447a28e10ef7CVE reference, Linux
- https://git.kernel.org/stable/c/133f5e2a37ce08c82d24e8fba65e0a81deae4609CVE reference, Linux
- https://git.kernel.org/stable/c/230ca758453c63bd38e4d9f4a21db698f7abada8CVE reference, Linux
- https://lists.debian.org/debian-lts-announce/2025/05/msg00045.htmlCVE reference, CVE
- https://lists.debian.org/debian-lts-announce/2025/05/msg00030.htmlCVE reference, CVE
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.