CVE-2026-89147 PUBLISHED

Net-SNMP through 5.9.5.2 Denial of Service via Blocking Unauthenticated SMUX Read

Assigner: VulnCheck
Reserved: 11.09.2026 Published: 11.09.2026 Updated: 11.09.2026

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.

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	net-snmp
Product	Net-SNMP
Versions	Default: unaffected affected from 0 to 5.9.5.2 (incl.)

CVE-2026-89147 PUBLISHED

Net-SNMP through 5.9.5.2 Denial of Service via Blocking Unauthenticated SMUX Read

Metrics

Product Status

Credits

References

Problem Types