In the Linux kernel, the following vulnerability has been resolved: nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()… (CVE-2026-89677)
A vulnerability in the Linux kernel's NFS server code (nfsd) was fixed to address a potential issue where the function fh_compose() could be called with an incorrect dentry in nfsd4_create_file(). This could occur if dentry_create() returned a different dentry than expected, potentially leading to use-after-free scenarios. The fix involves deferring the fh_compose() call until the final dentry is confirmed. No CVSS score is available for this issue.
AI Analysis
Technical Summary
The Linux kernel vulnerability (CVE-2026-89677) involves the nfsd4_create_file() function in the NFS server implementation. The function dentry_create() may return a different dentry than the one passed in, for example, if the exported filesystem is NFS and the server returns a filehandle matching a directory already in the dcache. This unexpected behavior could cause the previously stored dentry to be freed and later dereferenced, leading to potential memory corruption. The patch moves the fh_compose() call to after the final dentry is confirmed, preventing use-after-free conditions.
Potential Impact
If exploited, this vulnerability could lead to use-after-free conditions in the kernel, potentially causing system instability or crashes. The input data does not specify any known exploits in the wild or direct impact beyond this memory management issue.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to address this issue by adjusting the timing of the fh_compose() call. Users should apply the official kernel updates that include this patch once available. Patch status is not explicitly confirmed in the input, so check the vendor advisory for current remediation guidance.
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()… (CVE-2026-89677)
Description
A vulnerability in the Linux kernel's NFS server code (nfsd) was fixed to address a potential issue where the function fh_compose() could be called with an incorrect dentry in nfsd4_create_file(). This could occur if dentry_create() returned a different dentry than expected, potentially leading to use-after-free scenarios. The fix involves deferring the fh_compose() call until the final dentry is confirmed. No CVSS score is available for this issue.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel vulnerability (CVE-2026-89677) involves the nfsd4_create_file() function in the NFS server implementation. The function dentry_create() may return a different dentry than the one passed in, for example, if the exported filesystem is NFS and the server returns a filehandle matching a directory already in the dcache. This unexpected behavior could cause the previously stored dentry to be freed and later dereferenced, leading to potential memory corruption. The patch moves the fh_compose() call to after the final dentry is confirmed, preventing use-after-free conditions.
Potential Impact
If exploited, this vulnerability could lead to use-after-free conditions in the kernel, potentially causing system instability or crashes. The input data does not specify any known exploits in the wild or direct impact beyond this memory management issue.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to address this issue by adjusting the timing of the fh_compose() call. Users should apply the official kernel updates that include this patch once available. Patch status is not explicitly confirmed in the input, so check the vendor advisory for current remediation guidance.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-rgqw-p3pf-j5p9
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-89677"]
Threat ID: 6aa4a00055bf5e2cf5a86608
Added to database: 09/12/2026, 00:42:40 UTC
Last enriched: 09/12/2026, 00:54:49 UTC
Last updated: 09/12/2026, 02:01:31 UTC
Views: 4
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