CVE-2026-64059: In the Linux kernel, the following vulnerability has been resolved: netfs: Fix folio->private handling in netfs_perform_write() Under some circumsta...

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".

Metrics

EPSS Probability

0.17%

6.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 8f52de0077ba3bf41e5d53d67a185700f41efce7, < 7f040243c74d72b45b22246c7d9e621fbeab44ac; >= 8f52de0077ba3bf41e5d53d67a185700f41efce7, < 551b5c71ee312ca7646ddb605231c1016e8cbb18; >= 8f52de0077ba3bf41e5d53d67a185700f41efce7, < 0969ea8370bad0e4fb6131b6a7bed9e7ec522ac7; >= 8f52de0077ba3bf41e5d53d67a185700f41efce7, < ccde2ac757c713535b224233a296de40efe5212d
Linux	Linux	6.12

References

Timeline

Published: Jul 19, 2026
Last Modified: Jul 30, 2026
Status: Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-64059?

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".

How severe is CVE-2026-64059?

Severity scoring for CVE-2026-64059 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.

How do I fix CVE-2026-64059?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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