In the Linux kernel, the following vulnerability has been resolved: netfs: fix VM_BUG_ON_FOLIO() issue in netfs_write_begin() call The multiple runs… (CVE-2026-64065)
A vulnerability in the Linux kernel's netfs subsystem involving the netfs_write_begin() function and VM_BUG_ON_FOLIO() check has been resolved. The issue could cause a kernel BUG at mm/filemap.c:1504, reproducible with about 30% probability using a specific test case. This bug leads to a kernel crash (BUG) triggered by improper folio locking state during write operations. The vulnerability was identified and fixed in the Linux kernel source code.
AI Analysis
Technical Summary
The Linux kernel contained a bug in the netfs_write_begin() function where the VM_BUG_ON_FOLIO() macro could trigger a kernel BUG due to folio locking state inconsistencies. This was reproducible by repeatedly running a generic test case, causing a kernel crash at mm/filemap.c line 1504. The issue was related to folio unlocking logic in the kernel's memory management and file mapping code. The vulnerability has been resolved by correcting the netfs_write_begin() implementation to prevent the kernel BUG from occurring.
Potential Impact
This vulnerability causes a kernel crash (kernel BUG) when triggered, leading to denial of service on affected systems. There is no information about privilege escalation or arbitrary code execution. The impact is limited to system stability and availability due to kernel panics.
Mitigation Recommendations
A fix for this vulnerability has been implemented in the Linux kernel source code. Users and administrators should update to a Linux kernel version that includes this fix. Since no vendor advisory or patch link is provided, check the official Linux kernel repositories or distribution updates for the corrected kernel version. Patch status is not yet confirmed from vendor advisory; verify with vendor or kernel maintainers for the exact fixed version.
In the Linux kernel, the following vulnerability has been resolved: netfs: fix VM_BUG_ON_FOLIO() issue in netfs_write_begin() call The multiple runs… (CVE-2026-64065)
Description
A vulnerability in the Linux kernel's netfs subsystem involving the netfs_write_begin() function and VM_BUG_ON_FOLIO() check has been resolved. The issue could cause a kernel BUG at mm/filemap.c:1504, reproducible with about 30% probability using a specific test case. This bug leads to a kernel crash (BUG) triggered by improper folio locking state during write operations. The vulnerability was identified and fixed in the Linux kernel source code.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel contained a bug in the netfs_write_begin() function where the VM_BUG_ON_FOLIO() macro could trigger a kernel BUG due to folio locking state inconsistencies. This was reproducible by repeatedly running a generic test case, causing a kernel crash at mm/filemap.c line 1504. The issue was related to folio unlocking logic in the kernel's memory management and file mapping code. The vulnerability has been resolved by correcting the netfs_write_begin() implementation to prevent the kernel BUG from occurring.
Potential Impact
This vulnerability causes a kernel crash (kernel BUG) when triggered, leading to denial of service on affected systems. There is no information about privilege escalation or arbitrary code execution. The impact is limited to system stability and availability due to kernel panics.
Mitigation Recommendations
A fix for this vulnerability has been implemented in the Linux kernel source code. Users and administrators should update to a Linux kernel version that includes this fix. Since no vendor advisory or patch link is provided, check the official Linux kernel repositories or distribution updates for the corrected kernel version. Patch status is not yet confirmed from vendor advisory; verify with vendor or kernel maintainers for the exact fixed version.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-23r9-pmc9-fcx4
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-64065"]
- Ecosystems
- []
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a5d27a92a4a8d598912c868
Added to database: 07/19/2026, 19:38:17 UTC
Last enriched: 07/19/2026, 19:53:47 UTC
Last updated: 07/20/2026, 15:19:15 UTC
Views: 12
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.