{"id":"CVE-2026-121450","kind":"vulnerability","aliases":["CVE-2026-121450"],"related":[],"title":"CFNext: subscription UUID leaks admin password through weak MD5 derivation","description":"CFNext before 3.1.0 contains a weak cryptographic derivation vulnerability that allows subscription link holders to recover the admin password because the subscription UUID is an MD5 of the password with a fixed public salt. Attackers can brute-force the password offline without rate limiting, log into the admin panel, and read stored Trojan, Clash, Telegram and Cloudflare API secrets.","summary":"CFNext before 3.1.0 derives each subscription UUID as an MD5 of the admin password using a fixed public salt. Anyone holding a subscription link can brute-force the password offline without rate limits, then log into the admin panel and read stored Trojan, Clash, Telegram and Cloudflare API secrets.","severity":"high","cvss":7.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["cfnext","cloudflare-workers","package","self-hosted"],"not_affected_if":["version-3.1.0-or-later"],"how_to_check":"- Check the CFNext version in the deployed project; versions below `3.1.0` are in scope.\n- Look for a subscription link that contains a UUID; if the UUID is an MD5 of the admin password, the derivation is in use.","fix":"- Move to `3.1.0` or later.","status":"open","published_at":"2026-11-03T16:17:23+00:00","first_seen_at":"2026-11-03T16:21:43+00:00","triaged_at":"2026-11-03T16:23:50+00:00","updated_at":"2026-11-03T16:23:50+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-03T16:23:50Z","model":"claude-haiku-5-5","output":{"fix":"- Move to `3.1.0` or later.","reach":"internet","title":"CFNext: subscription UUID leaks admin password through weak MD5 derivation","impact":"high","summary":"CFNext before 3.1.0 derives each subscription UUID as an MD5 of the admin password using a fixed public salt. Anyone holding a subscription link can brute-force the password offline without rate limits, then log into the admin panel and read stored Trojan, Clash, Telegram and Cloudflare API secrets.","audience":"businesses","category":"package","nicknames":[],"who_cares":["cfnext","self-hosted","cloudflare-workers"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"admin password recovered, stored proxy and Cloudflare API secrets readable","analyst_note":"","how_to_check":"- Check the CFNext version in the deployed project; versions below `3.1.0` are in scope.\n- Look for a subscription link that contains a UUID; if the UUID is an MD5 of the admin password, the derivation is in use.","plain_action":"","needs_analyst":false,"not_affected_if":["version-3.1.0-or-later"],"who_is_affected":"Teams that run CFNext before 3.1.0 and hand out subscription links to users. Anyone holding a subscription link can attempt to recover the admin password, so the link itself is the attack surface. Deployments that never shared subscription links are less exposed.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000688,"input_tokens":4191,"output_tokens":537,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-121450':13A,16A '-2026':12A,15A '3.1.0':27B,77C 'admin':5A,37B,63B,92C,123C 'allow':85C 'anyon':44B 'api':73B,133C 'attack':109C 'brute':51B,112C 'brute-forc':50B,111C 'cfnext':1A,17B,25B,75C 'clash':69B,129C 'cloudflar':19B,72B,132C 'cloudflare-work':18B 'contain':78C 'cryptograph':81C 'cve':11A,14A 'deriv':10A,28B,82C 'fix':41B,106C 'forc':52B,113C 'hold':45B 'holder':88C 'host':24B 'leak':4A 'limit':58B,119C 'link':48B,87C 'log':60B,120C 'md5':9A,34B,100C 'offlin':55B,116C 'packag':21B 'panel':64B,124C 'password':6A,38B,54B,93C,103C,115C 'public':42B,107C 'rate':57B,118C 'read':66B,126C 'recov':90C 'salt':43B,108C 'secret':74B,134C 'self':23B 'self-host':22B 'store':67B,127C 'subscript':2A,30B,47B,86C,96C 'telegram':70B,130C 'trojan':68B,128C 'use':39B 'uuid':3A,31B,97C 'vulner':83C 'weak':8A,80C 'without':56B,117C 'worker':20B","nicknames":[],"mitigations":[],"who_affected":"Teams that run CFNext before 3.1.0 and hand out subscription links to users. Anyone holding a subscription link can attempt to recover the admin password, so the link itself is the attack surface. Deployments that never shared subscription links are less exposed.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["cfnext","cloudflareworkers","high","package","selfhosted"],"first_public_at":"2026-11-03T16:17:23+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/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":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-121450","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121450","severity":null,"published_at":"2026-11-03T16:17:23+00:00","modified_at":"2026-11-03T16:17:23+00:00","first_seen_at":"2026-11-03T16:21:43+00:00","fetched_at":"2026-11-03T16:21:43+00:00","note":null}],"documents":[{"id":58809,"url":"https://github.com/PAICNI/CFNext/commit/ca8ad82bb7c635f765c82a1cd0c954fd70d81fb7","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":58810,"url":"https://www.vulncheck.com/advisories/cfnext-before-3.1.0-admin-password-recovery-via-md5-derived-subscription-uuid","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}