Answer in brief
CVE-2026-64158 records a Unknown severity vulnerability in netfs: Fix write streaming disablement if fd open O_RDWR. 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 | >=c38f4e96e605f17990e871214e6ea1496bc4e65f <9adf8e47d73d5e3c2fe77dea649dcde350ccd65c || >=c38f4e96e605f17990e871214e6ea1496bc4e65f <616578e40dcba3f94810d841c5a52b7e3bc8ede7 || >=c38f4e96e605f17990e871214e6ea1496bc4e65f <7a9fa5b020a3a40f8291a71cd44c08d931da430d || >=c38f4e96e605f17990e871214e6ea1496bc4e65f <70a7b9193bbbfceaab5974de66834c64ccc875dd | 9adf8e47d73d5e3c2fe77dea649dcde350ccd65c, 616578e40dcba3f94810d841c5a52b7e3bc8ede7, 7a9fa5b020a3a40f8291a71cd44c08d931da430d, 70a7b9193bbbfceaab5974de66834c64ccc875dd |
| Linux/Linuxgeneric | 6.8 | Not reported |
Published upstream
Jul 19, 2026
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: netfs: Fix write streaming disablement if fd open O_RDWR In netfs_perform_write(), "write streaming" (the caching of dirty data in dirty but !uptodate folios) is performed to avoid the need to read data that is just going to get immediately overwritten. However, this is/will be disabled in three circumstances: if the fd is open O_RDWR, if fscache is in use (as we need to round out the blocks for DIO) or if content encryption is enabled (again for rounding out purposes). The idea behind disabling it if the fd is open O_RDWR is that we'd need to flush the write-streaming page before we could read the data, particularly through mmap. But netfs now fills in the gaps if ->read_folio() is called on the page, so that is unnecessary. Further, this doesn't actually work if a separate fd is open for reading. Fix this by removing the check for O_RDWR, thereby allowing streaming writes even when we might read. This caused a number of problems with the generic/522 xfstest, but those are now fixed.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-64158 records a Unknown severity vulnerability in netfs: Fix write streaming disablement if fd open O_RDWR. 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 | >=c38f4e96e605f17990e871214e6ea1496bc4e65f <9adf8e47d73d5e3c2fe77dea649dcde350ccd65c || >=c38f4e96e605f17990e871214e6ea1496bc4e65f <616578e40dcba3f94810d841c5a52b7e3bc8ede7 || >=c38f4e96e605f17990e871214e6ea1496bc4e65f <7a9fa5b020a3a40f8291a71cd44c08d931da430d || >=c38f4e96e605f17990e871214e6ea1496bc4e65f <70a7b9193bbbfceaab5974de66834c64ccc875dd | 9adf8e47d73d5e3c2fe77dea649dcde350ccd65c, 616578e40dcba3f94810d841c5a52b7e3bc8ede7, 7a9fa5b020a3a40f8291a71cd44c08d931da430d, 70a7b9193bbbfceaab5974de66834c64ccc875dd |
| Linux/Linuxgeneric | 6.8 | Not reported |
Published upstream
Jul 19, 2026
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: netfs: Fix write streaming disablement if fd open O_RDWR In netfs_perform_write(), "write streaming" (the caching of dirty data in dirty but !uptodate folios) is performed to avoid the need to read data that is just going to get immediately overwritten. However, this is/will be disabled in three circumstances: if the fd is open O_RDWR, if fscache is in use (as we need to round out the blocks for DIO) or if content encryption is enabled (again for rounding out purposes). The idea behind disabling it if the fd is open O_RDWR is that we'd need to flush the write-streaming page before we could read the data, particularly through mmap. But netfs now fills in the gaps if ->read_folio() is called on the page, so that is unnecessary. Further, this doesn't actually work if a separate fd is open for reading. Fix this by removing the check for O_RDWR, thereby allowing streaming writes even when we might read. This caused a number of problems with the generic/522 xfstest, but those are now fixed.
Quoted source text, attributed separately from HOL analysis.