NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check (Linux Linux)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.44 % · percentile 39 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Linux
- NVD status
- Received
Description
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.
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
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H | Linux |
| CVSS 3.1 | HIGH 8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H | NVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary) |
European references
- ENISA EUVD · EUVD-2026-76623
- GCVE · GCVE-0-2026-89711
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1375 — Multiples vulnérabilités dans le noyau Linux de Debian LTS · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1289 — Multiples vulnérabilités dans le noyau Linux de Debian LTS · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1253 — Multiples vulnérabilités dans le noyau Linux de Debian · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| Linux · Linux | affected e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c < ae251937c6f0237e5b555a5e4ba4595b8206e865 ; affected e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c < e145e8d67a5d41c72d322e7f87ab474d39d9dfb7 ; affected e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c < 9f4434893a2783f7384d993cea883aff3fb7a52d ; affected e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c < 2ef131323999539038e306773c8256403834361b ; affected e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c < b55b4d880bb080fa10eb08ba21a5d8679b8102fe ; affected e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c < 7ef182a8fe9c12b0d936880b1e504840639aa009 |
| Linux · Linux | affected 4.8 ; unaffected 0 < 4.8 ; unaffected 5.10.270 ≤ 5.10.* ; unaffected 5.15.221 ≤ 5.15.* ; unaffected 6.1.188 ≤ 6.1.* ; unaffected 6.6.157 ≤ 6.6.* |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |