{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/products/nr1800x-9.1.0u.6279_b20210910/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[{"cvss":9.8,"id":"CVE-2026-7546"}],"_cs_exploited":false,"_cs_products":["NR1800X 9.1.0u.6279_B20210910"],"_cs_severities":["critical"],"_cs_tags":["cve","remote code execution","buffer overflow","router"],"_cs_type":"advisory","_cs_vendors":["Totolink"],"content_html":"\u003cp\u003eA critical security vulnerability, CVE-2026-7546, affects Totolink NR1800X routers running firmware version 9.1.0u.6279_B20210910. The vulnerability resides within the \u003ccode\u003efind_host_ip\u003c/code\u003e function of the lighttpd web server component. By exploiting this flaw, a remote, unauthenticated attacker can trigger a stack-based buffer overflow through manipulation of the Host argument in an HTTP request. The publicly disclosed exploit allows attackers to potentially gain complete control of the device. This vulnerability poses a significant risk to home and small business networks utilizing the affected Totolink router model, as successful exploitation leads to arbitrary code execution.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker identifies a vulnerable Totolink NR1800X router running firmware version 9.1.0u.6279_B20210910.\u003c/li\u003e\n\u003cli\u003eThe attacker crafts a malicious HTTP request targeting the router\u0026rsquo;s web interface.\u003c/li\u003e\n\u003cli\u003eThe crafted request includes a \u003ccode\u003eHost\u003c/code\u003e header with a string exceeding the buffer size allocated in the \u003ccode\u003efind_host_ip\u003c/code\u003e function within the \u003ccode\u003elighttpd\u003c/code\u003e component.\u003c/li\u003e\n\u003cli\u003eThe router\u0026rsquo;s \u003ccode\u003elighttpd\u003c/code\u003e server processes the HTTP request and passes the \u003ccode\u003eHost\u003c/code\u003e header value to the vulnerable function.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003efind_host_ip\u003c/code\u003e function attempts to store the oversized \u003ccode\u003eHost\u003c/code\u003e value in a stack-allocated buffer.\u003c/li\u003e\n\u003cli\u003eA stack-based buffer overflow occurs due to the insufficient buffer size.\u003c/li\u003e\n\u003cli\u003eThe overflow overwrites adjacent memory on the stack, potentially including the return address.\u003c/li\u003e\n\u003cli\u003eThe attacker gains arbitrary code execution on the device.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-7546 allows a remote attacker to execute arbitrary code on the vulnerable Totolink NR1800X device. This can lead to complete control of the router, allowing the attacker to modify router settings, intercept network traffic, or use the compromised router as a pivot point for further attacks within the network. Given the nature of stack-based buffer overflows, the attacker can potentially install persistent backdoors or malware. This presents a significant risk to users, potentially exposing sensitive data and infrastructure to unauthorized access.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eApply available patches released by Totolink to remediate CVE-2026-7546.\u003c/li\u003e\n\u003cli\u003eMonitor network traffic for suspicious HTTP requests targeting Totolink routers, specifically looking for abnormally long Host headers with the Sigma rule \u0026ldquo;Detect Suspiciously Long Host Header\u0026rdquo;.\u003c/li\u003e\n\u003cli\u003eImplement network segmentation to limit the impact of a compromised router.\u003c/li\u003e\n\u003cli\u003eReview and harden router configurations, including disabling remote administration if not required.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-01T03:16:01Z","date_published":"2026-05-01T03:16:01Z","id":"/briefs/2026-05-totolink-rce/","summary":"A stack-based buffer overflow vulnerability (CVE-2026-7546) in the Totolink NR1800X router allows remote attackers to achieve arbitrary code execution by sending a crafted HTTP request with a manipulated Host header to the vulnerable lighttpd component.","title":"Totolink NR1800X Stack-Based Buffer Overflow Vulnerability","url":"https://feed.craftedsignal.io/briefs/2026-05-totolink-rce/"},{"_cs_actors":[],"_cs_cves":[{"cvss":8.8,"id":"CVE-2026-7548"}],"_cs_exploited":false,"_cs_products":["NR1800X 9.1.0u.6279_B20210910"],"_cs_severities":["critical"],"_cs_tags":["command-injection","router","network"],"_cs_type":"advisory","_cs_vendors":["Totolink"],"content_html":"\u003cp\u003eA command injection vulnerability, identified as CVE-2026-7548, affects Totolink NR1800X router version 9.1.0u.6279_B20210910. The vulnerability resides within the \u003ccode\u003esub_41A68C\u003c/code\u003e function of the \u003ccode\u003e/cgi-bin/cstecgi.cgi\u003c/code\u003e file. By manipulating the \u003ccode\u003esetUssd\u003c/code\u003e argument, a remote attacker can inject arbitrary commands into the system. Publicly available exploit code makes exploitation easier. This vulnerability poses a significant risk as it allows unauthenticated remote attackers to execute arbitrary commands on the affected device, potentially leading to full system compromise.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker identifies a vulnerable Totolink NR1800X device running firmware version 9.1.0u.6279_B20210910.\u003c/li\u003e\n\u003cli\u003eThe attacker sends a crafted HTTP request to the \u003ccode\u003e/cgi-bin/cstecgi.cgi\u003c/code\u003e endpoint.\u003c/li\u003e\n\u003cli\u003eThe HTTP request includes the \u003ccode\u003esetUssd\u003c/code\u003e argument with a malicious payload designed to inject a command.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003esub_41A68C\u003c/code\u003e function processes the \u003ccode\u003esetUssd\u003c/code\u003e argument without proper sanitization.\u003c/li\u003e\n\u003cli\u003eThe injected command is executed by the system with the privileges of the web server process.\u003c/li\u003e\n\u003cli\u003eThe attacker gains initial access and can execute arbitrary commands on the device.\u003c/li\u003e\n\u003cli\u003eThe attacker may then use the command execution to escalate privileges, install malware, or pivot to other devices on the network.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of this vulnerability allows an attacker to execute arbitrary commands on the affected Totolink NR1800X router. This could lead to complete compromise of the device, allowing the attacker to control network traffic, modify router settings, or use the router as a pivot point to attack other devices on the network. Given the wide usage of Totolink routers, a large number of devices could be vulnerable.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor web server logs for requests to \u003ccode\u003e/cgi-bin/cstecgi.cgi\u003c/code\u003e containing suspicious characters or command injection attempts in the \u003ccode\u003esetUssd\u003c/code\u003e parameter, using the Sigma rule provided below.\u003c/li\u003e\n\u003cli\u003eImplement rate limiting on the \u003ccode\u003e/cgi-bin/cstecgi.cgi\u003c/code\u003e endpoint to mitigate brute-force exploitation attempts.\u003c/li\u003e\n\u003cli\u003eApply available patches provided by Totolink to address the CVE-2026-7548 vulnerability.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule to your SIEM and tune for your environment.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-01T03:16:01Z","date_published":"2026-05-01T03:16:01Z","id":"/briefs/2026-05-totolink-command-injection/","summary":"A command injection vulnerability exists in Totolink NR1800X version 9.1.0u.6279_B20210910, affecting the function sub_41A68C of the file /cgi-bin/cstecgi.cgi; by manipulating the argument setUssd, a remote attacker can inject commands, and an exploit is publicly available.","title":"Totolink NR1800X Command Injection Vulnerability","url":"https://feed.craftedsignal.io/briefs/2026-05-totolink-command-injection/"}],"language":"en","title":"CraftedSignal Threat Feed — NR1800X 9.1.0u.6279_B20210910","version":"https://jsonfeed.org/version/1.1"}