Answer in brief
CVE-2026-89711 records a High severity (CVSS 8.2) 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), 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.
CVSS is 8.2. 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), 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 |
| Linux/Linuxgeneric | >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <ae251937c6f0237e5b555a5e4ba4595b8206e865 || >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <e145e8d67a5d41c72d322e7f87ab474d39d9dfb7 || >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <9f4434893a2783f7384d993cea883aff3fb7a52d || >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <2ef131323999539038e306773c8256403834361b || >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <b55b4d880bb080fa10eb08ba21a5d8679b8102fe || >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <7ef182a8fe9c12b0d936880b1e504840639aa009 || >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <a275de3bac5635514ca830f2e46b5ff0e66b5c4c || >=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e | ae251937c6f0237e5b555a5e4ba4595b8206e865, e145e8d67a5d41c72d322e7f87ab474d39d9dfb7, 9f4434893a2783f7384d993cea883aff3fb7a52d, 2ef131323999539038e306773c8256403834361b, b55b4d880bb080fa10eb08ba21a5d8679b8102fe, 7ef182a8fe9c12b0d936880b1e504840639aa009, a275de3bac5635514ca830f2e46b5ff0e66b5c4c, aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e |
Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 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.