CVE-2026-89711NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check
Updated under an hour ago ()
Does this affect you?
It affects Linux. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
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.
- CVSS
- 8.2 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c before ae251937c6f0237e5b555a5e4ba4595b8206e865; from e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c before e145e8d67a5d41c72d322e7f87ab474d39d9dfb7; from e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c before 9f4434893a2783f7384d993cea883aff3fb7a52d; from e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c before 2ef131323999539038e306773c8256403834361b; from e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c before b55b4d880bb080fa10eb08ba21a5d8679b8102fe; from e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c before 7ef182a8fe9c12b0d936880b1e504840639aa009; from e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c before a275de3bac5635514ca830f2e46b5ff0e66b5c4c; from e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c before aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e | CNA record |
References
- https://git.kernel.org/stable/c/ae251937c6f0237e5b555a5e4ba4595b8206e865
- https://git.kernel.org/stable/c/e145e8d67a5d41c72d322e7f87ab474d39d9dfb7
- https://git.kernel.org/stable/c/9f4434893a2783f7384d993cea883aff3fb7a52d
- https://git.kernel.org/stable/c/2ef131323999539038e306773c8256403834361b
- https://git.kernel.org/stable/c/b55b4d880bb080fa10eb08ba21a5d8679b8102fe
- https://git.kernel.org/stable/c/7ef182a8fe9c12b0d936880b1e504840639aa009
- https://git.kernel.org/stable/c/a275de3bac5635514ca830f2e46b5ff0e66b5c4c
- https://git.kernel.org/stable/c/aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.