CVE-2026-89677

CRITICALCVSS 9.8/10EPSS 0.16%

Last modified

CVE-2026-89677 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file() dentry_create() can hypothetically provide a different dentry than the one passed in. This could happen, for example, if the exported filesystem is NFS, and the server returned to OPEN a filehandle which matched a directory that was already in the dcache. EPSS estimates a 0.16% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file() dentry_create() can hypothetically provide a different dentry than the one passed in. This could happen, for example, if the exported filesystem is NFS, and the server returned to OPEN a filehandle which matched a directory that was already in the dcache. Clearly this would not be expected! If this were to happen the dentry (child) that was already stored in resfhp could be freed and later dereferenced. We shouldn't call fh_compose() until we are certain that we have the final dentry, so this patch moved the fh_compose() call to two places: one for the case where the target already exists, and one after dentry_create() where it was created.

Metrics

EPSS Probability
0.16%

5.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

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

VendorProductVersions
LinuxLinux>= 64a989dbd144e0622371396461b11335459692d2, < 033e783709ce99662cf81f6abcad746a8da9d35f; >= 64a989dbd144e0622371396461b11335459692d2, < 3e2c79360c6a89975ec5b5a7d4ef937e4db91a27
LinuxLinux7.0

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-89677?
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file() dentry_create() can hypothetically provide a different dentry than the one passed in. This could happen, for example, if the exported filesystem is NFS, and the server returned to OPEN a filehandle which matched a directory that was already in the dcache. Clearly this would not be expected! If this were to happen the dentry (child) that was already stored in resfhp could be freed and later dereferenced. We shouldn't call fh_compose() until we are certain that we have the final dentry, so this patch moved the fh_compose() call to two places: one for the case where the target already exists, and one after dentry_create() where it was created.
How severe is CVE-2026-89677?
CVE-2026-89677 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.
How do I fix CVE-2026-89677?
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