CVE-2026-80899

UnknownEPSS 0.14%

Last modified

CVE-2026-80899 is a vulnerability of currently unknown severity. 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. EPSS estimates a 0.14% chance of exploitation in the next 30 days.

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/20260619135800.1594811-1-michael.bommarito@gmail.com

Metrics

EPSS Probability
0.14%

4.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

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

VendorProductVersions
LinuxLinux>= a1bafc3109d713ed83f73d61ba5cb1e6fd80fdbc, < f6145794f17a27d25f8a84edb80731fb0e07c196; >= a1bafc3109d713ed83f73d61ba5cb1e6fd80fdbc, < c37460cd9b2fcb61ec66b7eb4fde737e65ec2a56
LinuxLinux6.9

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-80899?
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/20260619135800.1594811-1-michael.bommarito@gmail.com
How severe is CVE-2026-80899?
Severity scoring for CVE-2026-80899 is pending analysis. The EPSS model estimates a 0.14% probability of exploitation in the next 30 days.
How do I fix CVE-2026-80899?
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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Source: NVD / NIST