{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/cve-2026-8836/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":9.8,"id":"CVE-2026-8836"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["lwIP (\u003c= 2.2.1)"],"_cs_severities":["critical"],"_cs_tags":["snmp","buffer_overflow","rce","CVE-2026-8836"],"_cs_type":"advisory","_cs_vendors":[],"content_html":"\u003cp\u003eA stack-based buffer overflow vulnerability, identified as CVE-2026-8836, has been discovered in lwIP versions up to 2.2.1. The vulnerability resides within the \u003ccode\u003esnmpv3 USM Handler\u003c/code\u003e component, specifically in the \u003ccode\u003esnmp_parse_inbound_frame\u003c/code\u003e function of the \u003ccode\u003esrc/apps/snmp/snmp_msg.c\u003c/code\u003e file. By manipulating the \u003ccode\u003emsgAuthenticationParameters\u003c/code\u003e argument, a remote attacker can trigger a buffer overflow, potentially leading to arbitrary code execution. The patch addressing this vulnerability is identified by the commit hash \u003ccode\u003e0c957ec03054eb6c8205e9c9d1d05d90ada3898c\u003c/code\u003e. This vulnerability poses a significant risk as it can be exploited remotely without authentication.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker identifies a vulnerable lwIP instance with SNMPv3 USM enabled.\u003c/li\u003e\n\u003cli\u003eThe attacker crafts a malicious SNMPv3 packet targeting the \u003ccode\u003esnmp_parse_inbound_frame\u003c/code\u003e function.\u003c/li\u003e\n\u003cli\u003eThe crafted packet includes a \u003ccode\u003emsgAuthenticationParameters\u003c/code\u003e argument designed to exceed the buffer\u0026rsquo;s capacity.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003esnmp_parse_inbound_frame\u003c/code\u003e function processes the malformed SNMPv3 packet without proper bounds checking.\u003c/li\u003e\n\u003cli\u003eThe oversized \u003ccode\u003emsgAuthenticationParameters\u003c/code\u003e argument overwrites adjacent memory on the stack, including return addresses.\u003c/li\u003e\n\u003cli\u003eUpon function return, the overwritten return address is used, redirecting execution flow to attacker-controlled code.\u003c/li\u003e\n\u003cli\u003eThe attacker gains arbitrary code execution within the context of the lwIP process.\u003c/li\u003e\n\u003cli\u003eThe attacker can then use this code execution to further compromise the system, potentially leading to data exfiltration or denial of service.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-8836 allows a remote attacker to execute arbitrary code on the vulnerable system. Given the widespread use of lwIP in embedded devices and network appliances, a large number of devices are potentially affected. A successful attack could lead to complete system compromise, allowing the attacker to steal sensitive data, disrupt network services, or use the compromised device as a bot in a larger botnet. The CVSS v3.1 score of 9.8 highlights the critical severity of this vulnerability.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eApply the patch identified by commit hash \u003ccode\u003e0c957ec03054eb6c8205e9c9d1d05d90ada3898c\u003c/code\u003e to address the buffer overflow.\u003c/li\u003e\n\u003cli\u003eMonitor network traffic for malformed SNMPv3 packets, especially those with unusually large \u003ccode\u003emsgAuthenticationParameters\u003c/code\u003e using the provided Sigma rules.\u003c/li\u003e\n\u003cli\u003eConsider disabling SNMPv3 USM if it is not required to reduce attack surface.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect CVE-2026-8836 Exploitation Attempt via Malformed SNMP Packet\u0026rdquo; to detect potential exploitation attempts.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-18T19:17:57Z","date_published":"2026-05-18T19:17:57Z","id":"https://feed.craftedsignal.io/briefs/2026-05-lwip-snmp-overflow/","summary":"A stack-based buffer overflow vulnerability (CVE-2026-8836) exists in lwIP up to version 2.2.1 within the snmpv3 USM Handler, allowing remote attackers to execute arbitrary code by manipulating the `msgAuthenticationParameters` argument in the `snmp_parse_inbound_frame` function.","title":"lwIP SNMPv3 USM Handler Stack-Based Buffer Overflow (CVE-2026-8836)","url":"https://feed.craftedsignal.io/briefs/2026-05-lwip-snmp-overflow/"}],"language":"en","title":"CraftedSignal Threat Feed — CVE-2026-8836","version":"https://jsonfeed.org/version/1.1"}