Answer in brief
CVE-2026-31403 records a High severity (CVSS 7.8) vulnerability in NFSD: Hold net reference for the lifetime of /proc/fs/nfs/exports fd. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-31403 records a High severity (CVSS 7.8) vulnerability in NFSD: Hold net reference for the lifetime of /proc/fs/nfs/exports fd. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. 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), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <76740c28050dc6db2f5550f1325b00a11bbb3255 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <c7f406fb341d6747634b8b1fa5461656e5e56076 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <d1a19217995df9c7e4118f5a2820c5032fef2945 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <e3d77f935639e6ae4b381c80464c31df998d61f4 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <db4a9f99b12a7ee1c19d86c83a3b752c7effa6c6 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <6a8d70e2ad6aad2c345a5048edcb8168036f97d6 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <e7fcf179b82d3a3730fd8615da01b087cc654d0b | 76740c28050dc6db2f5550f1325b00a11bbb3255, c7f406fb341d6747634b8b1fa5461656e5e56076, d1a19217995df9c7e4118f5a2820c5032fef2945, e3d77f935639e6ae4b381c80464c31df998d61f4, db4a9f99b12a7ee1c19d86c83a3b752c7effa6c6, 6a8d70e2ad6aad2c345a5048edcb8168036f97d6, e7fcf179b82d3a3730fd8615da01b087cc654d0b |
| Linux/Linuxgeneric | 3.9 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
Published upstream
Apr 3, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 14, 2026
In the Linux kernel, the following vulnerability has been resolved: NFSD: Hold net reference for the lifetime of /proc/fs/nfs/exports fd The /proc/fs/nfs/exports proc entry is created at module init and persists for the module's lifetime. exports_proc_open() captures the caller's current network namespace and stores its svc_export_cache in seq->private, but takes no reference on the namespace. If the namespace is subsequently torn down (e.g. container destruction after the opener does setns() to a different namespace), nfsd_net_exit() calls nfsd_export_shutdown() which frees the cache. Subsequent reads on the still-open fd dereference the freed cache_detail, walking a freed hash table. Hold a reference on the struct net for the lifetime of the open file descriptor. This prevents nfsd_net_exit() from running -- and thus prevents nfsd_export_shutdown() from freeing the cache -- while any exports fd is open. cache_detail already stores its net pointer (cd->net, set by cache_create_net()), so exports_release() can retrieve it without additional per-file storage.
Quoted source text, attributed separately from HOL analysis.
CVSS is 7.8. 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), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <76740c28050dc6db2f5550f1325b00a11bbb3255 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <c7f406fb341d6747634b8b1fa5461656e5e56076 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <d1a19217995df9c7e4118f5a2820c5032fef2945 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <e3d77f935639e6ae4b381c80464c31df998d61f4 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <db4a9f99b12a7ee1c19d86c83a3b752c7effa6c6 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <6a8d70e2ad6aad2c345a5048edcb8168036f97d6 || >=96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5 <e7fcf179b82d3a3730fd8615da01b087cc654d0b | 76740c28050dc6db2f5550f1325b00a11bbb3255, c7f406fb341d6747634b8b1fa5461656e5e56076, d1a19217995df9c7e4118f5a2820c5032fef2945, e3d77f935639e6ae4b381c80464c31df998d61f4, db4a9f99b12a7ee1c19d86c83a3b752c7effa6c6, 6a8d70e2ad6aad2c345a5048edcb8168036f97d6, e7fcf179b82d3a3730fd8615da01b087cc654d0b |
| Linux/Linuxgeneric | 3.9 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
Published upstream
Apr 3, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 14, 2026
In the Linux kernel, the following vulnerability has been resolved: NFSD: Hold net reference for the lifetime of /proc/fs/nfs/exports fd The /proc/fs/nfs/exports proc entry is created at module init and persists for the module's lifetime. exports_proc_open() captures the caller's current network namespace and stores its svc_export_cache in seq->private, but takes no reference on the namespace. If the namespace is subsequently torn down (e.g. container destruction after the opener does setns() to a different namespace), nfsd_net_exit() calls nfsd_export_shutdown() which frees the cache. Subsequent reads on the still-open fd dereference the freed cache_detail, walking a freed hash table. Hold a reference on the struct net for the lifetime of the open file descriptor. This prevents nfsd_net_exit() from running -- and thus prevents nfsd_export_shutdown() from freeing the cache -- while any exports fd is open. cache_detail already stores its net pointer (cd->net, set by cache_create_net()), so exports_release() can retrieve it without additional per-file storage.
Quoted source text, attributed separately from HOL analysis.