CVE-2026-8836

CRITICAL

lwIP snmpv3 USM snmp_msg.c snmp_parse_inbound_frame stack-based overflow

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-8836. PoCs published by Hunt-Benito.

AI-analyzed exploit summary This repository contains a functional exploit for CVE-2026-8836, a stack-based buffer overflow in lwIP's SNMPv3 USM handler. The exploit constructs a malicious SNMPv3 packet with an oversized msgAuthenticationParameters field to trigger the vulnerability.

Description

A vulnerability was found in lwIP up to 2.2.1. Affected is the function snmp_parse_inbound_frame of the file src/apps/snmp/snmp_msg.c of the component snmpv3 USM Handler. Performing a manipulation of the argument msgAuthenticationParameters results in stack-based buffer overflow. The attack may be initiated remotely. The patch is named 0c957ec03054eb6c8205e9c9d1d05d90ada3898c. It is suggested to install a patch to address this issue.

Exploits (1)

github WORKING POC
by Hunt-Benito · pythonpoc
https://github.com/Hunt-Benito/lwip-snmpv3-stack-overflow-cve-2026-8836-critical-embedded-rce

This repository contains a functional exploit for CVE-2026-8836, a stack-based buffer overflow in lwIP's SNMPv3 USM handler. The exploit constructs a malicious SNMPv3 packet with an oversized msgAuthenticationParameters field to trigger the vulnerability.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: lwIP <= 2.2.1 with LWIP_SNMP_V3 enabled
No auth needed
Prerequisites: Network access to the target device · SNMPv3 service enabled on the target
devstral-2 · analyzed May 31, 2026 Full analysis →

References (6)

Core 6
Core References
Vdb Entry, Technical Description vdb-entry technical-description
VDB-364474 | lwIP snmpv3 USM snmp_msg.c snmp_parse_inbound_frame stack-based overflow
https://vuldb.com/vuln/364474
Signature, Permissions Required signature permissions-required
VDB-364474 | CTI Indicators (IOB, IOC, IOA)
https://vuldb.com/vuln/364474/cti
Third Party Advisory third-party-advisory
Submit #829798 | lwIP 2.1.0 Stack-based Buffer Overflow
https://vuldb.com/submit/829798
Broken Link broken-link
https://savannah.nongnu.org/bugs/?68194

Scores

CVSS v3 9.8
EPSS 0.0028
EPSS Percentile 52.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact total

Details

CWE
CWE-119 CWE-121
Status published
Products (6)
None/lwIP 2.1.0
None/lwIP 2.1.1
None/lwIP 2.1.2
None/lwIP 2.1.3
None/lwIP 2.2.0
None/lwIP 2.2.1
Published May 18, 2026
Tracked Since May 19, 2026