CVE-2026-64059
netfs: Fix folio->private handling in netfs_perform_write()
Description
In the Linux kernel, the following vulnerability has been resolved: netfs: Fix folio->private handling in netfs_perform_write() Under some circumstances, netfs_perform_write() doesn't correctly manipulate folio->private between NULL, NETFS_FOLIO_COPY_TO_CACHE, pointing to a group and pointing to a netfs_folio struct, leading to potential multiple attachments of private data with associated folio ref leaks and also leaks of netfs_folio structs or netfs_group refs. Fix this by consolidating the place at which a folio is marked uptodate in one place and having that look at what's attached to folio->private and decide how to clean it up and then set the new group. Also, the content shouldn't be flushed if group is NULL, even if a group is specified in the netfs_group parameter, as that would be the case for a new folio. A filesystem should always specify netfs_group or never specify netfs_group. The Sashiko auto-review tool noted that it was theoretically possible that the fpos >= ctx->zero_point section might leak if it modified a streaming write folio. This is unlikely, but with a network filesystem, third party changes can happen. It also pointed out that __netfs_set_group() would leak if called multiple times on the same folio from the "whole folio modify section".
INFO
Published Date :
July 19, 2026, 4:17 p.m.
Last Modified :
July 19, 2026, 4:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-64059
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Consolidate folio uptodate marking.
- Ensure correct cleanup of folio->private.
- Validate netfs_group specification.
- Review folio modify section for leaks.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-64059.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64059 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-64059
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-64059 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64059 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 19, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '8f52de0077ba3bf41e5d53d67a185700f41efce7', 'lessThan': '7f040243c74d72b45b22246c7d9e621fbeab44ac', 'versionType': 'git'}, {'status': 'affected', 'version': '8f52de0077ba3bf41e5d53d67a185700f41efce7', 'lessThan': '551b5c71ee312ca7646ddb605231c1016e8cbb18', 'versionType': 'git'}, {'status': 'affected', 'version': '8f52de0077ba3bf41e5d53d67a185700f41efce7', 'lessThan': '0969ea8370bad0e4fb6131b6a7bed9e7ec522ac7', 'versionType': 'git'}, {'status': 'affected', 'version': '8f52de0077ba3bf41e5d53d67a185700f41efce7', 'lessThan': 'ccde2ac757c713535b224233a296de40efe5212d', 'versionType': 'git'}], 'programFiles': ['fs/netfs/buffered_write.c', 'include/trace/events/netfs.h'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.12'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.12', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.92', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.34', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.11', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/netfs/buffered_write.c', 'include/trace/events/netfs.h'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: netfs: Fix folio->private handling in netfs_perform_write() Under some circumstances, netfs_perform_write() doesn't correctly manipulate folio->private between NULL, NETFS_FOLIO_COPY_TO_CACHE, pointing to a group and pointing to a netfs_folio struct, leading to potential multiple attachments of private data with associated folio ref leaks and also leaks of netfs_folio structs or netfs_group refs. Fix this by consolidating the place at which a folio is marked uptodate in one place and having that look at what's attached to folio->private and decide how to clean it up and then set the new group. Also, the content shouldn't be flushed if group is NULL, even if a group is specified in the netfs_group parameter, as that would be the case for a new folio. A filesystem should always specify netfs_group or never specify netfs_group. The Sashiko auto-review tool noted that it was theoretically possible that the fpos >= ctx->zero_point section might leak if it modified a streaming write folio. This is unlikely, but with a network filesystem, third party changes can happen. It also pointed out that __netfs_set_group() would leak if called multiple times on the same folio from the "whole folio modify section". Added Reference https://git.kernel.org/stable/c/0969ea8370bad0e4fb6131b6a7bed9e7ec522ac7 Added Reference https://git.kernel.org/stable/c/551b5c71ee312ca7646ddb605231c1016e8cbb18 Added Reference https://git.kernel.org/stable/c/7f040243c74d72b45b22246c7d9e621fbeab44ac Added Reference https://git.kernel.org/stable/c/ccde2ac757c713535b224233a296de40efe5212d