---
title: "CVE-2026-89147: Net-SNMP - Denial of Service"
description: "Net-SNMP through 5.9.5.2 contains a denial of service caused by unauthenticated blocking read without timeout in the SMUX module's smux_accept(), letting unauthenticated remote clients block SNMP processing indefinitely, exploit requires network access to SMUX listener."
url: https://panop.io/threat-heartbeat/CVE-2026-89147/
---

# CVE-2026-89147 Net-SNMP - Denial of Service

Net-SNMP through 5.9.5.2 contains a denial of service caused by unauthenticated blocking read without timeout in the SMUX module's smux\_accept(), letting unauthenticated remote clients block SNMP processing indefinitely, exploit requires network access to SMUX listener.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.49% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89147)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

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

Published

11 September 2026

Updated

15 October 2026

Weakness

[CWE-400](https://cwe.mitre.org/data/definitions/400.html)

## Vendor fix

Update to the latest version beyond 5.9.5.2.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-89147](https://nvd.nist.gov/vuln/detail/CVE-2026-89147)
- [https://gist.github.com/thesmartshadow/001cea595e75fed6aaea7389666dc9eb](https://gist.github.com/thesmartshadow/001cea595e75fed6aaea7389666dc9eb)
- [https://github.com/net-snmp/net-snmp](https://github.com/net-snmp/net-snmp)
- [https://github.com/net-snmp/net-snmp/blob/v5.9.5.2/agent/mibgroup/smux/smux.c](https://github.com/net-snmp/net-snmp/blob/v5.9.5.2/agent/mibgroup/smux/smux.c)
- [https://www.vulncheck.com/advisories/net-snmp-through-5.9.5.2-denial-of-service-via-blocking-unauthenticated-smux-read](https://www.vulncheck.com/advisories/net-snmp-through-5.9.5.2-denial-of-service-via-blocking-unauthenticated-smux-read)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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