CVE-2026-89147Network attack vectorHinoki check available

Service hang via blocking unauthenticated SMUX read

Published Sep 11, 2026 · Updated Sep 15, 2026

Denial of service in Net-SNMP through 5.9.5.2 allows remote attackers to suspend SNMP processing through an idle SMUX connection. The SMUX accept path performs a blocking read without a timeout before authenticating the newly accepted client, stalling the single-threaded snmpd main loop. The SMUX listener must be built, enabled, and remotely reachable; one client that connects without sending data can hang all SNMP request handling.

CVSS severityUnavailable
Unscored
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Denial of service in Net-SNMP through 5.9.5.2 allows remote attackers to suspend SNMP processing through an idle SMUX connection. The SMUX accept path performs a blocking read without a timeout before authenticating the newly accepted client, stalling the single-threaded snmpd main loop. The SMUX listener must be built, enabled, and remotely reachable; one client that connects without sending data can hang all SNMP request handling.

The record

CVE
CVE-2026-89147
Published
Sep 11, 2026
Updated
Sep 15, 2026
Vendor
Net-SNMP
Product
Net-SNMP
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 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=0 <=5.9.5.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Net-SNMP · Net-SNMPversion=0 <=5.9.5.2

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application 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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