CVE-2026-89711

CVE CVE-2026-89711EUVD EUVD-2026-76623Published 2026-09-11T19:46:26.000ZLast changed 2026-09-14T12:02:10.000ZCVSS 8.2

What the advisory describes

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.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

Linux — Linux patch: 6.18.50; e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <a275de3bac5635514ca830f2e46b5ff0e66b5c4c; patch: 6.1.188; e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <e145e8d67a5d41c72d322e7f87ab474d39d9dfb7; patch: 0; e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e; 4.8; e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <7ef182a8fe9c12b0d936880b1e504840639aa009; patch: 6.6.157; e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <ae251937c6f0237e5b555a5e4ba4595b8206e865; patch: 7.3-rc1; patch: 5.10.270; e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <2ef131323999539038e306773c8256403834361b; e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <9f4434893a2783f7384d993cea883aff3fb7a52d; e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <b55b4d880bb080fa10eb08ba21a5d8679b8102fe; patch: 7.2.4; patch: 5.15.221; patch: 6.12.109

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

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Linux — Linux

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