{"id":"CVE-2026-121618","kind":"vulnerability","aliases":["CVE-2026-121618"],"related":[],"title":"Linksys E5600 router: factory test CGI leaks information remotely","description":"A weakness has been identified in Linksys E5600 1.1.0.26. This affects an unknown part of the file /cgi-bin/fqc.cgi of the component Factory Quality Control. This manipulation causes information disclosure. Remote exploitation of the attack is possible. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way. This vulnerability only affects products that are no longer supported by the maintainer.","summary":"A weakness in the Factory Quality Control CGI script (/cgi-bin/fqc.cgi) of Linksys E5600 firmware 1.1.0.26 lets a remote attacker disclose information. A public exploit exists, and the vendor did not respond to the disclosure.","severity":"medium","cvss":5.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["e5600","firmware","home-router","infrastructure","linksys"],"not_affected_if":["cgi-not-exposed","different-firmware"],"how_to_check":"- Check the firmware version on the router's admin page and look for `1.1.0.26`\n- Test whether `/cgi-bin/fqc.cgi` responds on the device from the network","fix":null,"status":"open","published_at":"2026-11-04T03:17:15+00:00","first_seen_at":"2026-11-04T03:46:40+00:00","triaged_at":"2026-11-04T03:47:15+00:00","updated_at":"2026-11-04T03:47:15+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-11-04T03:47:15Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"internet","title":"Linksys E5600 router: factory test CGI leaks information remotely","impact":"low","summary":"A weakness in the Factory Quality Control CGI script (/cgi-bin/fqc.cgi) of Linksys E5600 firmware 1.1.0.26 lets a remote attacker disclose information. A public exploit exists, and the vendor did not respond to the disclosure.","audience":"everyone","category":"infrastructure","nicknames":[],"who_cares":["linksys","e5600","home-router","firmware"],"confidence":0.6,"fix_status":"none","needs_auth":"unknown","worst_case":"remote attacker reads information from the router","analyst_note":"Confirm whether fqc.cgi is reachable on WAN by default and what data it returns; see the NVD entry at https://nvd.nist.gov/vuln/detail/CVE-2026-121618.","how_to_check":"- Check the firmware version on the router's admin page and look for `1.1.0.26`\n- Test whether `/cgi-bin/fqc.cgi` responds on the device from the network\n- unknown for anything beyond these checks","plain_action":"If you own a Linksys E5600 router, check whether its firmware is 1.1.0.26; the maker has not released a fix, so consider replacing the router.","needs_analyst":true,"not_affected_if":["different-firmware","cgi-not-exposed"],"who_is_affected":"Owners of Linksys E5600 routers running firmware 1.1.0.26, where the Factory Quality Control CGI is reachable. The sources say the product is no longer supported by the maintainer, so no patch is expected. Devices not running this firmware or without this CGI exposed are not described as affected.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000735,"input_tokens":4171,"output_tokens":636,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-121618':12A,15A '-2026':11A,14A '/cgi-bin/fqc.cgi':32B,74C '1.1.0.26':37B,65C 'affect':67C,126C 'attack':41B,90C,107C 'avail':98C 'caus':83C 'cgi':6A,30B 'compon':77C 'contact':111C 'control':29B,80C 'could':103C 'cve':10A,13A 'disclos':42B 'disclosur':56B,85C,115C 'e5600':2A,16B,35B,64C 'earli':112C 'exist':47B 'exploit':46B,87C,94C 'factori':4A,27B,78C 'file':73C 'firmwar':17B,36B 'home':19B 'home-rout':18B 'identifi':61C 'inform':8A,43B,84C 'infrastructur':21B 'leak':7A 'let':38B 'linksi':1A,22B,34B,63C 'longer':131C 'made':97C 'maintain':135C 'manipul':82C 'part':70C 'possibl':92C 'product':127C 'public':45B,101C 'qualiti':28B,79C 'remot':9A,40B,86C 'respond':53B,119C 'router':3A,20B 'script':31B 'support':132C 'test':5A 'unknown':69C 'use':105C 'vendor':50B,109C 'vulner':124C 'way':122C 'weak':24B,58C","nicknames":[],"mitigations":[],"who_affected":"Owners of Linksys E5600 routers running firmware 1.1.0.26, where the Factory Quality Control CGI is reachable. The sources say the product is no longer supported by the maintainer, so no patch is expected. Devices not running this firmware or without this CGI exposed are not described as affected.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"everyone","plain_action":"If you own a Linksys E5600 router, check whether its firmware is 1.1.0.26; the maker has not released a fix, so consider replacing the router.","pkeys":[],"ptokens":[],"labels":["e5600","firmware","homerouter","infrastructure","linksys","medium"],"campaign_type":null,"first_public_at":"2026-11-04T03:17:15+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"cna@vuldb.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-121618","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121618","severity":null,"published_at":"2026-11-04T03:17:15+00:00","modified_at":"2026-11-04T03:17:15+00:00","first_seen_at":"2026-11-04T03:46:40+00:00","fetched_at":"2026-11-04T03:46:40+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}