{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","favicon":"https://feed.craftedsignal.io/favicon-32x32.png","feed_url":"https://feed.craftedsignal.io/tags/cve-2026-19811/feed.json","home_page_url":"https://feed.craftedsignal.io/","icon":"https://feed.craftedsignal.io/apple-touch-icon.png","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":8.8,"id":"CVE-2026-19811"}],"_cs_exploited":true,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["A800R (4.1.2cu.5137_B20200730)"],"_cs_severities":["high"],"_cs_tags":["remote-code-execution","cve-2026-19811","router-vulnerability"],"_cs_type":"threat","_cs_vendors":["TOTOLINK"],"content_html":"\u003cp\u003eA critical security vulnerability has been identified in the TOTOLINK A800R router, specifically affecting firmware version 4.1.2cu.5137_B20200730. The flaw resides within the firewall.so component, specifically in the setIpQosRules function invoked by the /cgi-bin/cstecgi.cgi script. An attacker can exploit this via a stack-based buffer overflow by manipulating the 'Comment' argument. The vulnerability is remotely exploitable by an authenticated user and has been assigned CVE-2026-19811. Public exploit code is currently available, increasing the risk of active exploitation against vulnerable network devices. Given the nature of the device as an edge gateway, successful exploitation could provide an attacker with persistent access to the network.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker performs reconnaissance to identify the target web management interface on a publicly accessible TOTOLINK A800R router.\u003c/li\u003e\n\u003cli\u003eAttacker gains valid credentials for the administrative or user portal through credential stuffing or brute-forcing.\u003c/li\u003e\n\u003cli\u003eAttacker accesses the Quality of Service (QoS) settings page which invokes the /cgi-bin/cstecgi.cgi CGI script.\u003c/li\u003e\n\u003cli\u003eAttacker crafts a malicious HTTP POST request targeting the setIpQosRules function.\u003c/li\u003e\n\u003cli\u003eAttacker injects a specially crafted, oversized string into the 'Comment' parameter of the HTTP request.\u003c/li\u003e\n\u003cli\u003eThe firewall.so component fails to properly validate the input size, resulting in a stack-based buffer overflow.\u003c/li\u003e\n\u003cli\u003eThe overflow overwrites the return address on the stack, diverting program execution to attacker-controlled shellcode.\u003c/li\u003e\n\u003cli\u003eAttacker gains execution context, potentially leading to full system compromise or persistence on the device.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows an authenticated remote attacker to achieve arbitrary code execution on the TOTOLINK A800R device. This compromises the integrity and confidentiality of traffic passing through the router, facilitates lateral movement into the local network, and provides a platform for further exploitation of connected internal systems.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor web server logs for anomalies targeting /cgi-bin/cstecgi.cgi and specifically unusual values or excessive lengths in the 'Comment' parameter.\u003c/li\u003e\n\u003cli\u003eDisable remote management access for the router's web interface, restricting access to trusted local IP addresses only.\u003c/li\u003e\n\u003cli\u003eEvaluate the need for the device's current firmware version and apply vendor security updates if a patch addressing CVE-2026-19811 is available from TOTOLINK.\u003c/li\u003e\n\u003cli\u003eAudit access logs for any unauthorized authentication attempts or patterns consistent with credential exploitation.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-08-14T08:06:33Z","date_published":"2026-08-14T08:06:33Z","id":"https://feed.craftedsignal.io/briefs/2026-08-totolink-buffer-overflow/","summary":"An authenticated remote attacker can trigger a stack-based buffer overflow in the TOTOLINK A800R router via the setIpQosRules function, potentially leading to arbitrary code execution.","title":"Remote Stack-based Buffer Overflow in TOTOLINK A800R","url":"https://feed.craftedsignal.io/briefs/2026-08-totolink-buffer-overflow/"}],"language":"en","title":"CraftedSignal Threat Feed - Cve-2026-19811","version":"https://jsonfeed.org/version/1.1"}