# CVE-2026-89677: linux: In the Linux kernel, the following vulnerability has been resolved:  nfsd: fix possible fh_compose of wrong dentry in...

CVE-2026-89677 is fixed in linux on 1 platform by DEBIAN-CVE-2026-89677 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-89677
- Priority: Urgent
- CVSS: 9.8 (critical)
- EPSS: 0.0055
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 11, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-89677](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89677.md) | Sep 23, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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