CVE-2026-89711Network attack vector

Host panic via NFS re-export lookup warning

Published Sep 11, 2026 · Updated Sep 11, 2026

Improper exceptional-condition handling in Linux kernel NFSD allows remote attackers to trigger a kernel warning through NFS re-export lookups. nfsd_mode_check() wrongly executes WARN_ON_ONCE when a re-export dentry lacks i_op->lookup, although nfserr_notdir safely blocks the subsequent NULL method call. Reachability requires client access to an NFS re-export; the warning logs diagnostics by default but panics the host when panic_on_warn is enabled.

CVSS severityUnavailable
Unscored
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper exceptional-condition handling in Linux kernel NFSD allows remote attackers to trigger a kernel warning through NFS re-export lookups. nfsd_mode_check() wrongly executes WARN_ON_ONCE when a re-export dentry lacks i_op->lookup, although nfserr_notdir safely blocks the subsequent NULL method call. Reachability requires client access to an NFS re-export; the warning logs diagnostics by default but panics the host when panic_on_warn is enabled.

The record

CVE
CVE-2026-89711
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.8
  2. Affected versionversion=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <7ef182a8fe9c12b0d936880b1e504840639aa009
  3. Affected versionversion=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <a275de3bac5635514ca830f2e46b5ff0e66b5c4c
  4. Affected versionversion=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e
  5. Affected versionversion=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <b55b4d880bb080fa10eb08ba21a5d8679b8102fe

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=4.8; version=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <7ef182a8fe9c12b0d936880b1e504840639aa009; version=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <a275de3bac5635514ca830f2e46b5ff0e66b5c4c; version=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e; version=e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c <b55b4d880bb080fa10eb08ba21a5d8679b8102fe

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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