CVE-2026-23109: fs/writeback: skip AS_NO_DATA_INTEGRITY mappings in wait_sb_inodes()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-04 · updated 2026-06-17
Weakness: CWE-835

Description

In the Linux kernel, the following vulnerability has been resolved: fs/writeback: skip AS_NO_DATA_INTEGRITY mappings in wait_sb_inodes() Above the while() loop in wait_sb_inodes(), we document that we must wait for all pages under writeback for data integrity. Consequently, if a mapping, like fuse, traditionally does not have data integrity semantics, there is no need to wait at all; we can simply skip these inodes. This restores fuse back to prior behavior where syncs are no-ops. This fixes a user regression where if a system is running a faulty fuse server that does not reply to issued write requests, this causes wait_sb_inodes() to wait forever.

Affected products

Linux kernel: from 6.16 before 6.18.8; 6.19-rc1, 6.19-rc2, 6.19-rc3, 6.19-rc4, 6.19-rc5, 6.19-rc6 — fixed in 6.18.8

How to fix

Upgrade to a fixed version: Linux kernel 6.18.8. Check the vendor advisory for mitigations.

References

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