Answer in brief
CVE-2025-40212 records a Unknown severity vulnerability in nfsd: fix refcount leak in nfsd_set_fh_dentry(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <b6bc86ce3944b10b9fc181fc00c1a520a20ed965 || >=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <c83d7365cec5eb5ebeeee2a72e29b4ca58a7e4c2 || >=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c | b6bc86ce3944b10b9fc181fc00c1a520a20ed965, c83d7365cec5eb5ebeeee2a72e29b4ca58a7e4c2, 8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c |
| Linux/Linuxgeneric | 6.12 | Not reported |
Published upstream
Nov 24, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2025-40212 records a Unknown severity vulnerability in nfsd: fix refcount leak in nfsd_set_fh_dentry(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <b6bc86ce3944b10b9fc181fc00c1a520a20ed965 || >=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <c83d7365cec5eb5ebeeee2a72e29b4ca58a7e4c2 || >=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c | b6bc86ce3944b10b9fc181fc00c1a520a20ed965, c83d7365cec5eb5ebeeee2a72e29b4ca58a7e4c2, 8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c |
| Linux/Linuxgeneric | 6.12 | Not reported |
Published upstream
Nov 24, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.