Resource exhaustion in Net-Snmp
CVE-2026-89147
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.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.005 (41.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 41.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
Weakness classification (CWE)
References
- gist.github.com/thesmartshadow/001cea595e75fed6aaea7389666dc9eb (third-party-advisory)
- github.com/net-snmp/net-snmp/blob/v5.9.5.2/agent/mibgroup/smux/smux.c (technical-description)
- github.com/net-snmp/net-snmp (product)
- www.vulncheck.com/advisories/net-snmp-through-5.9.5.2-denial-of-service-via-blo… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-89147?
- CVE-2026-89147 is a high-severity vulnerability in Net-Snmp, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-09-11.
- How severe is CVE-2026-89147?
- High severity. CVSS v3 base score is 7.5 out of 10.