What’s Vulnerable › Vulnerabilities

CVE-2026-89697: nfsd: add fh_want_write() for early-verified SETATTR in nfsd_proc_setattr()

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-11 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: add fh_want_write() for early-verified SETATTR in nfsd_proc_setattr() The BOTH_TIME_SET branch calls fh_verify() early so setattr_prepare() can inspect the dentry. This causes nfsd_setattr() to skip fh_want_write(), so notify_change() runs without a mount write reference. Add the missing fh_want_write() call after the early fh_verify().

Affected products

• Linux kernel: from 3.18.46 before 3.19; 4.2 — fixed in 3.19, 7.3

How to fix

Upgrade to a fixed version: Linux kernel 3.19, 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/15ca3b64a69caa6194bed8f98a20ed90a11c11dd
• https://git.kernel.org/stable/c/2150305134889fb2fc25228d35353bd2f6f29500
• https://git.kernel.org/stable/c/3eec9d791968c177a4a8cda9af5c04f79dae09cb
• https://git.kernel.org/stable/c/4e475be769aa9f7a2c1ce55a2b8592cfccacddcc
• https://git.kernel.org/stable/c/533964d420d385e11b08dd4c56c66ef5dcccaf08
• https://git.kernel.org/stable/c/9229d824b938f4fb0ea7a5dddade51735e6fe6f9
• https://git.kernel.org/stable/c/c4a409b86a92815181a8e9395c6bf1696ad19175
• https://git.kernel.org/stable/c/d823bf9285cdf4514873b85ab5a888878dd4e8f4

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