{"id":"CVE-2026-121434","kind":"vulnerability","aliases":["CVE-2026-121434"],"related":[],"title":"Froxlor: customers with API access can replace managed HTTPS certificates","description":"Froxlor 2.3.0 before 2.3.15 contains a missing authorization check in the Certificates.add and Certificates.update API commands, which do not verify whether a domain's certificate is Let's Encrypt-managed. Customers with API access can overwrite the managed certificate and private key with an attacker-chosen pair, which a REBUILD_VHOST task deploys to the webserver, breaking HTTPS and desynchronizing ACME automation.","summary":"Froxlor 2.3.0 before 2.3.15 lacks an authorization check in its Certificates API, so customers can overwrite a domain's Let's Encrypt-managed certificate and private key with their own pair. The attacker-chosen pair is deployed to the web server, which breaks HTTPS for the domain and desynchronizes ACME automation.","severity":"medium","cvss":5.4,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["froxlor","hosting","other","self-hosted"],"not_affected_if":["default-config","no-customer-api-access"],"how_to_check":"- Check the installed Froxlor version, for example in the admin panel footer or `froxlor/lib/version.php`, and see whether it is before `2.3.15`.\n- Check whether customers have API keys enabled for the Certificates API commands.","fix":"- Froxlor versions from `2.3.0` up to but not including `2.3.15`: move to `2.3.15` or later.","status":"open","published_at":"2026-11-03T15:17:34+00:00","first_seen_at":"2026-11-03T15:22:00+00:00","triaged_at":"2026-11-03T15:23:25+00:00","updated_at":"2026-11-03T15:23:25+00:00","category":"other","confidence":0.7,"triage":{"at":"2026-11-03T15:23:25Z","model":"claude-haiku-5-5","output":{"fix":"- Froxlor versions from `2.3.0` up to but not including `2.3.15`: move to `2.3.15` or later.","reach":"network","title":"Froxlor: customers with API access can replace managed HTTPS certificates","impact":"medium","summary":"Froxlor 2.3.0 before 2.3.15 lacks an authorization check in its Certificates API, so customers can overwrite a domain's Let's Encrypt-managed certificate and private key with their own pair. The attacker-chosen pair is deployed to the web server, which breaks HTTPS for the domain and desynchronizes ACME automation.","audience":"businesses","category":"other","nicknames":[],"who_cares":["froxlor","self-hosted","hosting"],"confidence":0.7,"fix_status":"available","needs_auth":"yes","worst_case":"Attacker-chosen certificate deployed, breaking HTTPS for domains","analyst_note":"","how_to_check":"- Check the installed Froxlor version, for example in the admin panel footer or `froxlor/lib/version.php`, and see whether it is before `2.3.15`.\n- Check whether customers have API keys enabled for the Certificates API commands.","plain_action":"","needs_analyst":false,"not_affected_if":["default-config","no-customer-api-access"],"who_is_affected":"Hosting providers running Froxlor 2.3.0 through 2.3.14 where customers have API access. The risk depends on customers being able to use the Certificates API against domains that have Let's Encrypt-managed certificates. Installations without customer API access are much less exposed.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000713,"input_tokens":4222,"output_tokens":582,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-121434':13A,16A '-2026':12A,15A '2.3.0':24B,77C '2.3.15':26B,79C 'access':5A,110C 'acm':74B,138C 'api':4A,34B,90C,109C 'attack':57B,122C 'attacker-chosen':56B,121C 'author':29B,83C 'autom':75B,139C 'break':67B,134C 'certif':10A,33B,47B,100C,115C 'certificates.add':87C 'certificates.update':89C 'check':30B,84C 'chosen':58B,123C 'command':91C 'contain':80C 'custom':2A,36B,107C 'cve':11A,14A 'deploy':61B,130C 'desynchron':73B,137C 'domain':40B,71B,98C 'encrypt':45B,105C 'encrypt-manag':44B,104C 'froxlor':1A,17B,23B,76C 'host':18B,22B 'https':9A,68B,135C 'key':50B,118C 'lack':27B 'let':42B,102C 'manag':8A,46B,106C,114C 'miss':82C 'overwrit':38B,112C 'pair':54B,59B,124C 'privat':49B,117C 'rebuild':127C 'replac':7A 'self':21B 'self-host':20B 'server':65B 'task':129C 'verifi':95C 'vhost':128C 'web':64B 'webserv':133C 'whether':96C","nicknames":[],"mitigations":[],"who_affected":"Hosting providers running Froxlor 2.3.0 through 2.3.14 where customers have API access. The risk depends on customers being able to use the Certificates API against domains that have Let's Encrypt-managed certificates. Installations without customer API access are much less exposed.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["froxlor","hosting","medium","other","selfhosted"],"first_public_at":"2026-10-20T07:23:53+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/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-2026-121434","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121434","severity":null,"published_at":"2026-11-03T15:17:34+00:00","modified_at":"2026-11-03T15:17:34+00:00","first_seen_at":"2026-11-03T15:22:00+00:00","fetched_at":"2026-11-03T15:22:00+00:00","note":null}],"documents":[{"id":58393,"url":"https://github.com/froxlor/froxlor/security/advisories/GHSA-ch7m-649m-x7xg","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-20T07:23:53+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":58394,"url":"https://www.vulncheck.com/advisories/froxlor-2.3.0-before-2.3.15-authorization-bypass-via-certificates-update-api","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"}