CVE-2026-89147

EUVD-2026-76036
Net-SNMP through 5.9.5.2 contains a denial of service vulnerability in the SMUX module where smux_accept() performs an unauthenticated blocking read without timeout on newly accepted connections. An unauthenticated remote client can connect to the SMUX listener and send no data, causing the single-threaded snmpd main loop to block indefinitely and suspend all SNMP processing.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
7.5 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: 41.59%
Debian logo
Debian Releases
Debian Product
Codename
net-snmp
bookworm
postponed
bookworm (security)
vulnerable
forky
5.9.5.2+dfsg-3
fixed
sid
5.9.5.2+dfsg-3
fixed
trixie
no-dsa
trixie (security)
vulnerable
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
net-snmp
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
trusty
needs-triage
xenial
needs-triage
Common Weakness Enumeration
References
https://gist.github.com/thesmartshadow/001cea595e75fed6aaea7389666dc9eb
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://www.vulncheck.com/advisories/net-snmp-through-5.9.5.2-denial-of-service-via-blocking-unauthenticated-smux-read
https://gist.github.com/thesmartshadow/001cea595e75fed6aaea7389666dc9eb