CVE-2026-74389

System crash via unratelimited mailbox error logging

Published Aug 15, 2026 · Updated Aug 15, 2026

Denial of service in the Linux kernel allows local users to crash the system after an RDMA/hns hardware mailbox failure. Error paths after hns_roce_cmd_mbox() and its context wrappers use unrestricted ibdev_err() and ibdev_warn() calls, allowing repeated failures to flood the kernel log. Exploitation requires local low-privileged access and abnormal hns RDMA hardware behavior; the reported consequence is limited to availability.

CVSS severity4.7
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel allows local users to crash the system after an RDMA/hns hardware mailbox failure. Error paths after hns_roce_cmd_mbox() and its context wrappers use unrestricted ibdev_err() and ibdev_warn() calls, allowing repeated failures to flood the kernel log. Exploitation requires local low-privileged access and abnormal hns RDMA hardware behavior; the reported consequence is limited to availability.

The record

CVE
CVE-2026-74389
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=4.9
  2. Affected versionversion=9a4435375cd151e07c0c38fa601b00115986091b <66f44ec974ab372e4e1ee9eac4245237c94e8f68
  3. Affected versionversion=9a4435375cd151e07c0c38fa601b00115986091b <7d9fbee252f84de3e6947a40eec01481c9d8afbb
  4. Affected versionversion=9a4435375cd151e07c0c38fa601b00115986091b <bbd97d71e53e551890e4115ad9de46b5f2ac0858
  5. Affected versionversion=9a4435375cd151e07c0c38fa601b00115986091b <f3c9e84268e9fa613d40d6c138fb6969c35879b5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.9; version=9a4435375cd151e07c0c38fa601b00115986091b <66f44ec974ab372e4e1ee9eac4245237c94e8f68; version=9a4435375cd151e07c0c38fa601b00115986091b <7d9fbee252f84de3e6947a40eec01481c9d8afbb; version=9a4435375cd151e07c0c38fa601b00115986091b <bbd97d71e53e551890e4115ad9de46b5f2ac0858; version=9a4435375cd151e07c0c38fa601b00115986091b <f3c9e84268e9fa613d40d6c138fb6969c35879b5

Published CVSS scores

4.7SUSECVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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