{"id":"CVE-2026-126421","kind":"vulnerability","aliases":["CVE-2026-126421"],"related":[],"title":"OpenEMR: unbounded count parameter lets authenticated users exhaust PHP workers","description":"OpenEMR before 8.5.0 contains an uncontrolled resource consumption vulnerability that allows authenticated users with patients/med access to exhaust PHP workers via an unbounded count parameter. Attackers can send print_labels requests to labs_ajax.php with huge counts, forcing mPDF page and barcode generation that makes OpenEMR unavailable.","summary":"OpenEMR before 8.5.0 accepts an unbounded count parameter in print_labels requests to labs_ajax.php. An authenticated user with patients/med access can force huge mPDF and barcode generation and make the application unavailable.","severity":"medium","cvss":5.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["healthcare","openemr","package","php","self-hosted"],"not_affected_if":["no-patients-med-users","openemr-8.5.0-or-later"],"how_to_check":"- Check the installed OpenEMR version against the fixed release `8.5.0`\n- Review whether `labs_ajax.php` is reachable by users who hold the patients/med permission","fix":"- OpenEMR: move to `8.5.0` or later","status":"open","published_at":"2026-11-13T10:17:48+00:00","first_seen_at":"2026-11-13T10:47:21+00:00","triaged_at":"2026-11-13T10:57:18+00:00","updated_at":"2026-11-13T10:57:18+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-13T10:57:18Z","model":"claude-haiku-5-5","output":{"fix":"- OpenEMR: move to `8.5.0` or later","reach":"network","title":"OpenEMR: unbounded count parameter lets authenticated users exhaust PHP workers","impact":"low","summary":"OpenEMR before 8.5.0 accepts an unbounded count parameter in print_labels requests to labs_ajax.php. An authenticated user with patients/med access can force huge mPDF and barcode generation and make the application unavailable.","audience":"businesses","category":"package","nicknames":[],"who_cares":["openemr","self-hosted","healthcare","php"],"confidence":0.7,"fix_status":"available","needs_auth":"yes","worst_case":"application becomes unavailable through worker exhaustion","analyst_note":"","how_to_check":"- Check the installed OpenEMR version against the fixed release `8.5.0`\n- Review whether `labs_ajax.php` is reachable by users who hold the patients/med permission\n- unknown for further checks","plain_action":"","product_name":"","needs_analyst":false,"not_affected_if":["openemr-8.5.0-or-later","no-patients-med-users"],"who_is_affected":"Clinics and organizations that run OpenEMR self-hosted before 8.5.0 and have users with the patients/med permission. Exposure needs a valid login with that role; installations on 8.5.0 or later are not affected by this issue.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000717,"input_tokens":4620,"output_tokens":510,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-126421':13A,16A '-2026':12A,15A '8.5.0':26B,58C 'accept':27B 'access':43B,71C 'allow':66C 'applic':54B 'attack':81C 'authent':6A,39B,67C 'barcod':49B,96C 'consumpt':63C 'contain':59C 'count':3A,30B,79C,91C 'cve':11A,14A 'exhaust':8A,73C 'forc':45B,92C 'generat':50B,97C 'healthcar':17B 'host':23B 'huge':46B,90C 'label':34B,85C 'labs_ajax.php':37B,88C 'let':5A 'make':52B,99C 'mpdf':47B,93C 'openemr':1A,18B,24B,56C,100C 'packag':19B 'page':94C 'paramet':4A,31B,80C 'patients/med':42B,70C 'php':9A,20B,74C 'print':33B,84C 'request':35B,86C 'resourc':62C 'self':22B 'self-host':21B 'send':83C 'unavail':55B,101C 'unbound':2A,29B,78C 'uncontrol':61C 'user':7A,40B,68C 'via':76C 'vulner':64C 'worker':10A,75C","nicknames":[],"mitigations":[],"who_affected":"Clinics and organizations that run OpenEMR self-hosted before 8.5.0 and have users with the patients/med permission. Exposure needs a valid login with that role; installations on 8.5.0 or later are not affected by this issue.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["healthcare","medium","openemr","package","php","selfhosted"],"campaign_type":null,"search_a":"'-126421':13A,16A '-2026':12A,15A 'authent':6A 'count':3A 'cve':11A,14A 'exhaust':8A 'let':5A 'openemr':1A 'paramet':4A 'php':9A 'unbound':2A 'user':7A 'worker':10A","search_b":"'8.5.0':26B 'accept':27B 'access':43B 'applic':54B 'authent':39B 'barcod':49B 'count':30B 'forc':45B 'generat':50B 'healthcar':17B 'host':23B 'huge':46B 'label':34B 'labs_ajax.php':37B 'make':52B 'mpdf':47B 'openemr':18B,24B 'packag':19B 'paramet':31B 'patients/med':42B 'php':20B 'print':33B 'request':35B 'self':22B 'self-host':21B 'unavail':55B 'unbound':29B 'user':40B","search_c":"'8.5.0':58C 'access':71C 'allow':66C 'attack':81C 'authent':67C 'barcod':96C 'consumpt':63C 'contain':59C 'count':79C,91C 'exhaust':73C 'forc':92C 'generat':97C 'huge':90C 'label':85C 'labs_ajax.php':88C 'make':99C 'mpdf':93C 'openemr':56C,100C 'page':94C 'paramet':80C 'patients/med':70C 'php':74C 'print':84C 'request':86C 'resourc':62C 'send':83C 'unavail':101C 'unbound':78C 'uncontrol':61C 'user':68C 'via':76C 'vulner':64C 'worker':75C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-10-28T01:50:16+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/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-2026-126421","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-126421","severity":null,"published_at":"2026-11-13T10:17:48+00:00","modified_at":"2026-11-13T10:17:48+00:00","first_seen_at":"2026-11-13T10:47:21+00:00","fetched_at":"2026-11-13T10:47:21+00:00","note":null}],"documents":[{"id":145085,"url":"https://github.com/openemr/openemr/security/advisories/GHSA-3j3r-w7q7-h9fj","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-28T01:50:16+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":145086,"url":"https://www.vulncheck.com/advisories/openemr-before-8.5.0-denial-of-service-via-labs-ajax-php-label-count","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"}