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

What is CVE-2026-23109?

CVE-2026-23109 is a medium-severity denial of service vulnerability in Linux kernel, published on 4 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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.

Weakness: CWE-835

Which versions are affected by CVE-2026-23109?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-23109?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-23109 being exploited?

There is no known exploitation of CVE-2026-23109 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-23109, DEBIAN-CVE-2026-23109, GHSA-c47w-ggcw-5493, UBUNTU-CVE-2026-23109.