{"id":"CVE-2026-126771","kind":"vulnerability","aliases":["CVE-2026-126771"],"related":[],"title":"OpsTree REMS: uploaded attachments run scripts in other users' browsers","description":"OpsTree REMS through 1.0.0 contains a stored cross-site scripting vulnerability that allows authenticated attackers to inject scripts by uploading attachments with spoofed text/html Content-Type. Attackers can upload HTML files named like test.html.pdf that render in the REMS origin via Preview, executing JavaScript in victims' browsers.","summary":"OpsTree REMS through 1.0.0 accepts attachments with a spoofed text/html Content-Type, so a file named like test.html.pdf renders as HTML when previewed. An authenticated attacker can run JavaScript in the browsers of other users who open the preview.","severity":"medium","cvss":5.4,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["opstree-rems","other","self-hosted"],"not_affected_if":["no-attachment-uploads"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-11T19:17:37+00:00","first_seen_at":"2026-11-11T19:28:46+00:00","triaged_at":"2026-11-11T19:30:27+00:00","updated_at":"2026-11-11T19:30:27+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-11-11T19:30:27Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"OpsTree REMS: uploaded attachments run scripts in other users' browsers","impact":"medium","summary":"OpsTree REMS through 1.0.0 accepts attachments with a spoofed text/html Content-Type, so a file named like test.html.pdf renders as HTML when previewed. An authenticated attacker can run JavaScript in the browsers of other users who open the preview.","audience":"businesses","category":"other","nicknames":[],"who_cares":["opstree-rems","self-hosted"],"confidence":0.6,"fix_status":"unknown","needs_auth":"yes","worst_case":"Attacker runs scripts in other users' browsers within the REMS origin","analyst_note":"Check the NVD entry and the VulnCheck advisory for affected version range and any fixed release or mitigation.","how_to_check":"- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-attachment-uploads"],"who_is_affected":"Teams running OpsTree REMS through 1.0.0 where users can upload attachments and others preview them. The sources do not say whether a patched release exists. Installations without attachment uploads or without a logged-in user base are less exposed.","user_interaction":"yes","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000692,"input_tokens":4600,"output_tokens":463,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-126771':13A,16A '-2026':12A,15A '1.0.0':27B,67C 'accept':28B 'allow':77C 'attach':4A,29B,85C 'attack':50B,79C,92C 'authent':49B,78C 'browser':10A,56B,112C 'contain':68C 'content':35B,90C 'content-typ':34B,89C 'cross':72C 'cross-sit':71C 'cve':11A,14A 'execut':108C 'file':39B,96C 'host':23B 'html':45B,95C 'inject':81C 'javascript':53B,109C 'like':41B,98C 'name':40B,97C 'open':61B 'opstre':1A,18B,24B,64C 'opstree-rem':17B 'origin':105C 'preview':47B,63B,107C 'rem':2A,19B,25B,65C,104C 'render':43B,101C 'run':5A,52B 'script':6A,74C,82C 'self':22B 'self-host':21B 'site':73C 'spoof':32B,87C 'store':70C 'test.html.pdf':42B,99C 'text/html':33B,88C 'type':36B,91C 'upload':3A,84C,94C 'user':9A,59B 'via':106C 'victim':111C 'vulner':75C","nicknames":[],"mitigations":[],"who_affected":"Teams running OpsTree REMS through 1.0.0 where users can upload attachments and others preview them. The sources do not say whether a patched release exists. Installations without attachment uploads or without a logged-in user base are less exposed.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["medium","opstreerems","other","selfhosted"],"campaign_type":null,"search_a":"'-126771':13A,16A '-2026':12A,15A 'attach':4A 'browser':10A 'cve':11A,14A 'opstre':1A 'rem':2A 'run':5A 'script':6A 'upload':3A 'user':9A","search_b":"'1.0.0':27B 'accept':28B 'attach':29B 'attack':50B 'authent':49B 'browser':56B 'content':35B 'content-typ':34B 'file':39B 'host':23B 'html':45B 'javascript':53B 'like':41B 'name':40B 'open':61B 'opstre':18B,24B 'opstree-rem':17B 'preview':47B,63B 'rem':19B,25B 'render':43B 'run':52B 'self':22B 'self-host':21B 'spoof':32B 'test.html.pdf':42B 'text/html':33B 'type':36B 'user':59B","search_c":"'1.0.0':67C 'allow':77C 'attach':85C 'attack':79C,92C 'authent':78C 'browser':112C 'contain':68C 'content':90C 'content-typ':89C 'cross':72C 'cross-sit':71C 'execut':108C 'file':96C 'html':95C 'inject':81C 'javascript':109C 'like':98C 'name':97C 'opstre':64C 'origin':105C 'preview':107C 'rem':65C,104C 'render':101C 'script':74C,82C 'site':73C 'spoof':87C 'store':70C 'test.html.pdf':99C 'text/html':88C 'type':91C 'upload':84C,94C 'via':106C 'victim':111C 'vulner':75C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-11T19:17:37+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/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-2026-126771","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-126771","severity":null,"published_at":"2026-11-11T19:17:37+00:00","modified_at":"2026-11-11T19:17:37+00:00","first_seen_at":"2026-11-11T19:28:46+00:00","fetched_at":"2026-11-11T19:28:46+00:00","note":null}],"documents":[{"id":128101,"url":"https://www.vulncheck.com/advisories/opstree-rems-through-1.0.0-stored-xss-via-attachment-upload-and-preview","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"}