CVE-2026-80899
erofs: remove fscache backend entirely
Description
In the Linux kernel, the following vulnerability has been resolved: erofs: remove fscache backend entirely EROFS over fscache was introduced to provide image lazy pulling functionality. After the feature landed, the fscache subsystem made netfs a new hard dependency, which is unexpected for a local filesystem and has an kernel-defined caching hierarchy which could be inflexible compared to the fanotify pre-content hooks. Therefore, this feature has been deprecated for almost two years. As EROFS file-backed mounts and fanotify pre-content hooks both upstream for a while and already providing equivalent functionality (erofs-utils has supported fanotify pre-content hooks), let's remove the fscache backend now. The main application of this feature is Nydus [1], and they plan to move to use fanotify pre-content hooks in the near future too. I hope this patch can be merged into Linux 7.2, which is also motivated by newly found implementation issues [2][3] that are not worth investigating given the deprecation and limited development resources. The associated fscache/cachefiles cleanup patch will follow separately through the vfs tree (netfs) later: it seems fine since the codebase is isolated by CONFIG_CACHEFILES_ONDEMAND. [1] https://github.com/dragonflyoss/nydus/blob/v2.1.0/docs/nydus-fscache.md [2] https://github.com/dragonflyoss/nydus/pull/1824 [3] https://lore.kernel.org/r/[email protected]
INFO
Published Date :
Sept. 4, 2026, 6:17 p.m.
Last Modified :
Sept. 4, 2026, 6:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-80899
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
- Remove the EROFS fscache backend.
- Utilize fanotify pre-content hooks for functionality.
- Update Nydus to use fanotify pre-content hooks.
- Apply associated fscache/cachefiles cleanup patches.
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-2026-80899.
| URL | Resource |
|---|---|
| https://git.kernel.org/stable/c/c37460cd9b2fcb61ec66b7eb4fde737e65ec2a56 | |
| https://git.kernel.org/stable/c/f6145794f17a27d25f8a84edb80731fb0e07c196 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-80899 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-2026-80899
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-2026-80899 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-80899 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.
-
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 04, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: erofs: remove fscache backend entirely EROFS over fscache was introduced to provide image lazy pulling functionality. After the feature landed, the fscache subsystem made netfs a new hard dependency, which is unexpected for a local filesystem and has an kernel-defined caching hierarchy which could be inflexible compared to the fanotify pre-content hooks. Therefore, this feature has been deprecated for almost two years. As EROFS file-backed mounts and fanotify pre-content hooks both upstream for a while and already providing equivalent functionality (erofs-utils has supported fanotify pre-content hooks), let's remove the fscache backend now. The main application of this feature is Nydus [1], and they plan to move to use fanotify pre-content hooks in the near future too. I hope this patch can be merged into Linux 7.2, which is also motivated by newly found implementation issues [2][3] that are not worth investigating given the deprecation and limited development resources. The associated fscache/cachefiles cleanup patch will follow separately through the vfs tree (netfs) later: it seems fine since the codebase is isolated by CONFIG_CACHEFILES_ONDEMAND. [1] https://github.com/dragonflyoss/nydus/blob/v2.1.0/docs/nydus-fscache.md [2] https://github.com/dragonflyoss/nydus/pull/1824 [3] https://lore.kernel.org/r/[email protected] Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/80xxx/CVE-2026-80899.json">CVE-2026-80899</a> Added Reference https://git.kernel.org/stable/c/c37460cd9b2fcb61ec66b7eb4fde737e65ec2a56 Added Reference https://git.kernel.org/stable/c/f6145794f17a27d25f8a84edb80731fb0e07c196