Answer in brief
CVE-2026-89711 records a Unknown severity vulnerability in NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <b55b4d880bb080fa10eb08ba21a5d8679b8102fe || >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <7ef182a8fe9c12b0d936880b1e504840639aa009 || >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <a275de3bac5635514ca830f2e46b5ff0e66b5c4c || >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e | b55b4d880bb080fa10eb08ba21a5d8679b8102fe, 7ef182a8fe9c12b0d936880b1e504840639aa009, a275de3bac5635514ca830f2e46b5ff0e66b5c4c, aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e |
| Linux/Linuxgeneric | 4.8 | Not reported |
Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 11, 2026
In the Linux kernel, the following vulnerability has been resolved: NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check The header for commit e75b23f9e323 ("nfsd: check d_can_lookup in fh_verify of directories") details the assumption that justified adding the WARN_ON_ONCE to nfsd_mode_check(), that assumption is invalid (in the case of NFS reexport). When NFSD exports an NFS filesystem it is very possible for nfsd_mode_check() to encounter a @dentry that doesn't have i_op->lookup (see nfs_fhget()'s NFS_ATTR_FATTR_MOUNTPOINT and NFS_ATTR_FATTR_V4_REFERRAL handling, and d_flags_for_inode()). So remove nfsd_mode_check()'s WARN_ON_ONCE(). The nfserr_notdir return on that branch must stay. It guards the subsequent lookup_one_unlocked() -> __lookup_slow() path, which calls inode->i_op->lookup() with no NULL check, so returning nfserr_notdir is what keeps a client LOOKUP into such a @dentry from dereferencing a NULL method pointer.
Quoted source text, attributed separately from HOL analysis.