{"id":"CVE-2026-129134","kind":"vulnerability","aliases":["CVE-2026-129134"],"related":[],"title":"MRBS: forged Host header poisons password reset links, enabling account takeover","description":"MRBS before 1.13.0 contains a password reset poisoning vulnerability that allows unauthenticated attackers to redirect reset links by forging the Host header when $url_base is unset. Attackers can request a reset for a victim so AuthDb::notifyUser() emails a link pointing to their host, capturing the reset key when opened to take over accounts including administrators.","summary":"MRBS (a meeting room booking system) before 1.13.0 builds password reset links from the request's Host header when $url_base is unset. An unauthenticated attacker can make a reset email point to their own host and capture the reset key when the victim opens it, taking over the account, including administrator accounts.","severity":"high","cvss":8.6,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"MRBS","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["mrbs","package","php","self-hosted"],"not_affected_if":["url-base-set"],"how_to_check":"- Check the MRBS version in use; versions below `1.13.0` are in the affected range.\n- Check whether `$url_base` is set in the MRBS configuration; it is unset in the affected case.","fix":"- Upgrade MRBS to `1.13.0` or later.","status":"open","published_at":"2026-11-13T17:17:31+00:00","first_seen_at":"2026-11-13T17:48:01+00:00","triaged_at":"2026-11-13T17:48:43+00:00","updated_at":"2026-11-13T17:48:43+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-13T17:48:43Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade MRBS to `1.13.0` or later.\n- unknown","reach":"internet","title":"MRBS: forged Host header poisons password reset links, enabling account takeover","impact":"high","summary":"MRBS (a meeting room booking system) before 1.13.0 builds password reset links from the request's Host header when $url_base is unset. An unauthenticated attacker can make a reset email point to their own host and capture the reset key when the victim opens it, taking over the account, including administrator accounts.","audience":"businesses","category":"package","nicknames":[],"who_cares":["mrbs","self-hosted","php"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"attacker takes over accounts, including administrator accounts","analyst_note":"Confirm the fixed version and the $url_base default from the vendor advisory and release notes linked in the sources (github.com).","how_to_check":"- Check the MRBS version in use; versions below `1.13.0` are in the affected range.\n- Check whether `$url_base` is set in the MRBS configuration; it is unset in the affected case.\n- unknown","plain_action":"","product_name":"MRBS","needs_analyst":true,"not_affected_if":["url-base-set"],"who_is_affected":"MRBS instances below 1.13.0 where $url_base is not configured are exposed, since the reset link host comes from the forged Host header. Instances that set $url_base explicitly are not affected by this path. unknown for any further conditions, as the sources do not say.","user_interaction":"yes","product_ecosystem":"vendor","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000753,"input_tokens":4642,"output_tokens":577,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-129134':14A,17A '-2026':13A,16A '1.13.0':32B,80C 'account':10A,74B,77B,132C 'administr':76B,134C 'allow':88C 'attack':50B,90C,105C 'authdb':114C 'base':45B,102C 'book':29B 'build':33B 'captur':62B,123C 'contain':81C 'cve':12A,15A 'email':55B,116C 'enabl':9A 'forg':2A,96C 'header':4A,42B,99C 'host':3A,24B,41B,60B,98C,122C 'includ':75B,133C 'key':65B,126C 'link':8A,36B,94C,118C 'make':52B 'meet':27B 'mrbs':1A,18A,19B,25B,78C 'notifyus':115C 'open':69B,128C 'packag':20B 'password':6A,34B,83C 'php':21B 'point':56B,119C 'poison':5A,85C 'redirect':92C 'request':39B,107C 'reset':7A,35B,54B,64B,84C,93C,109C,125C 'room':28B 'self':23B 'self-host':22B 'system':30B 'take':71B,130C 'takeov':11A 'unauthent':49B,89C 'unset':47B,104C 'url':44B,101C 'victim':68B,112C 'vulner':86C","nicknames":[],"mitigations":[],"who_affected":"MRBS instances below 1.13.0 where $url_base is not configured are exposed, since the reset link host comes from the forged Host header. Instances that set $url_base explicitly are not affected by this path. unknown for any further conditions, as the sources do not say.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":["mrbs"],"ptokens":["mrbs"],"labels":["high","mrbs","package","php","selfhosted","vendor"],"campaign_type":null,"search_a":"'-129134':14A,17A '-2026':13A,16A 'account':10A 'cve':12A,15A 'enabl':9A 'forg':2A 'header':4A 'host':3A 'link':8A 'mrbs':1A,18A 'password':6A 'poison':5A 'reset':7A 'takeov':11A","search_b":"'1.13.0':32B 'account':74B,77B 'administr':76B 'attack':50B 'base':45B 'book':29B 'build':33B 'captur':62B 'email':55B 'header':42B 'host':24B,41B,60B 'includ':75B 'key':65B 'link':36B 'make':52B 'meet':27B 'mrbs':19B,25B 'open':69B 'packag':20B 'password':34B 'php':21B 'point':56B 'request':39B 'reset':35B,54B,64B 'room':28B 'self':23B 'self-host':22B 'system':30B 'take':71B 'unauthent':49B 'unset':47B 'url':44B 'victim':68B","search_c":"'1.13.0':80C 'account':132C 'administr':134C 'allow':88C 'attack':90C,105C 'authdb':114C 'base':102C 'captur':123C 'contain':81C 'email':116C 'forg':96C 'header':99C 'host':98C,122C 'includ':133C 'key':126C 'link':94C,118C 'mrbs':78C 'notifyus':115C 'open':128C 'password':83C 'point':119C 'poison':85C 'redirect':92C 'request':107C 'reset':84C,93C,109C,125C 'take':130C 'unauthent':89C 'unset':104C 'url':101C 'victim':112C 'vulner':86C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-12T19:06:47+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/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-2026-129134","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-129134","severity":null,"published_at":"2026-11-13T17:17:31+00:00","modified_at":"2026-11-13T17:17:31+00:00","first_seen_at":"2026-11-13T17:48:01+00:00","fetched_at":"2026-11-13T17:48:01+00:00","note":null}],"documents":[{"id":148137,"url":"https://github.com/meeting-room-booking-system/mrbs-code/commit/92f6f5610072ddb9e1b38074c410fc8be56947ed","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":148138,"url":"https://github.com/meeting-room-booking-system/mrbs-code/releases/tag/v1.13.0","title":"Release notes: github.com","kind":"release","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Release notes: github.com"},{"id":148147,"url":"https://github.com/meeting-room-booking-system/mrbs-code/security/advisories/GHSA-73cv-hx7f-9v27","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-11-12T19:06:47+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":148148,"url":"https://www.vulncheck.com/advisories/mrbs-before-1.13.0-password-reset-poisoning-via-host-header-injection","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"}],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}