CVE-2025-40212
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix refcount leak in nfsd_set_fh_dentry() nfsd exports a "pseudo root filesystem" which is used by NFSv4 to find the vari...
Affects 1 product across 6 vendors.
A refcount leak vulnerability was identified in the nfsd_set_fh_dentry() function of the Linux kernel, affecting the NFS daemon's handling of filehandles in the pseudo root filesystem.
BSID: BS-2025-GLOBAL-033643-I • Model: /workspace/models/qwen2.5-coder-32b-instruct-bf16 • Confidence: MEDIUM
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| CVE ID | CVE-2025-40212 |
|---|---|
| BSID | BS-2025-GLOBAL-033643-I BreachSpider Global ID |
| CVSS Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| Published | 2025-11-24 |
| Last Modified | 2026-10-18 |
| ICS Relevance | 0% |
| Source | NVD |
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix refcount leak in nfsd_set_fh_dentry() nfsd exports a "pseudo root filesystem" which is used by NFSv4 to find the various exported filesystems using LOOKUP requests from a known root filehandle. NFSv3 uses the MOUNT protocol to find those exported filesystems and so is not given access to the pseudo root filesystem. If a v3 (or v2) client uses a filehandle from that filesystem, nfsd_set_fh_dentry() will report an error, but still stores the export in "struct svc_fh" even though it also drops the reference (exp_put()). This means that when fh_put() is called an extra reference will be dropped which can lead to use-after-free and possible denial of service. Normal NFS usage will not provide a pseudo-root filehandle to a v3 client. This bug can only be triggered by the client synthesising an incorrect filehandle. To fix this we move the assignments to the svc_fh later, after all possible error cases have been detected.
Source: NIST NVD / MITRE CVE Database
An attacker could potentially exploit this vulnerability to cause a refcount leak, which could lead to memory exhaustion and denial of service. The vulnerability is specific to NFSv4, as NFSv3 does not have access to the pseudo root filesystem.
Exploitation Likelihood: MEDIUM
| Vendor | Product | Affected Versions |
|---|---|---|
| Client | — | — |
| Kernel | — | — |
| Linux | Linux | 6.12 |
| Lookup | — | — |
| Nfsv4 | — | — |
| Protocol | — | — |
No official vendor advisory link on record. See the CVE record →
| CISA known-exploited | Not in KEV catalog |
|---|---|
| Public Exploit | Not confirmed |
| PoC Code | Not confirmed |
AI Enrichment Record — provenance & audit hash
| Model | /workspace/models/qwen2.5-coder-32b-instruct-bf16 |
|---|---|
| Confidence | MEDIUM |
| Enriched At | 2026-05-24 |
| SHA-512 Audit Hash | afd67fbdaf8f327f9fea25e5835e7551e3f4dc6c0bcaa3abbf9008ebdcb4aa734365b0cc3af3a7d7e85d2eac57b2c835e8ca67bdfba430556bcd3261eff635c7 |
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