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NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-89711

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-89711

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
        "lessThan": "ae251937c6f0237e5b555a5e4ba4595b8206e865",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
        "lessThan": "e145e8d67a5d41c72d322e7f87ab474d39d9dfb7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
        "lessThan": "9f4434893a2783f7384d993cea883aff3fb7a52d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
        "lessThan": "2ef131323999539038e306773c8256403834361b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
        "lessThan": "b55b4d880bb080fa10eb08ba21a5d8679b8102fe",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
        "lessThan": "7ef182a8fe9c12b0d936880b1e504840639aa009",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
        "lessThan": "a275de3bac5635514ca830f2e46b5ff0e66b5c4c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
        "lessThan": "aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/nfsd/nfsfh.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.8"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.8",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.270",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.221",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.188",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.109",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.50",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.4",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/nfsd/nfsfh.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-89711

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#35192 · Revision 1
Added to Heist Feed
Publisher date
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