{"id":"CVE-2024-27443","kind":"vulnerability","aliases":["CVE-2024-27443"],"related":[],"title":"An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0","description":"An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. A Cross-Site Scripting (XSS) vulnerability exists in the CalendarInvite feature of the Zimbra webmail classic user interface, because of improper input validation in the handling of the calendar header. An attacker can exploit this via an email message containing a crafted calendar header with an embedded XSS payload. When a victim views this message in the Zimbra webmail classic interface, the payload is executed in the context of the victim's session, potentially leading to execution of arbitrary JavaScript code.","summary":"Zimbra Collaboration Suite's classic webmail interface has a cross-site scripting flaw in its CalendarInvite feature. A crafted calendar header in an email runs attacker-chosen JavaScript in the victim's browser session.","severity":"high","cvss":6.1,"epss":null,"exploited":true,"exploited_at":"2025-05-19T00:00:00+00:00","products":[{"name":"Synacor Zimbra Collaboration Suite (ZCS)","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"zimbra collaboration","fixed":["10.0.7"],"affected":">= 10.0.0, < 10.0.7","ecosystem":"vendor"},{"name":"zimbra collaboration","fixed":[],"affected":"= 9.0.0","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["email","exploited","package","self-hosted","zimbra"],"not_affected_if":["zimbra-modern-ui-only"],"how_to_check":null,"fix":"Apply the vendor mitigations per CISA guidance (vendor instructions not in sources); or discontinue use of the product if mitigations are unavailable.","status":"open","published_at":"2024-08-12T15:15:20+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T20:48:29+00:00","updated_at":"2026-10-23T22:29:05+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-23T20:48:29Z","model":"claude-haiku-5-5","output":{"fix":"Apply the vendor mitigations per CISA guidance (vendor instructions not in sources); or discontinue use of the product if mitigations are unavailable.","reach":"internet","summary":"Zimbra Collaboration Suite's classic webmail interface has a cross-site scripting flaw in its CalendarInvite feature. A crafted calendar header in an email runs attacker-chosen JavaScript in the victim's browser session.","category":"package","who_cares":["zimbra","self-hosted","email"],"confidence":0.6,"needs_auth":"no","worst_case":"Attacker runs JavaScript in victim's webmail session, reading mail and acting as the user.","analyst_note":"Find the Zimbra vendor advisory and the exact patched versions and mitigation steps; sources give none. Check https://www.cisa.gov/known-exploited-vulnerabilities-catalog for the KEV due date.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["zimbra-modern-ui-only"],"user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000459,"input_tokens":2633,"output_tokens":392,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2024':13A,16A '-27443':14A,17A '10.0':11A,80C '9.0':9A,78C 'arbitrari':160C 'attack':61B,113C 'attacker-chosen':60B 'browser':68B 'calendar':54B,110C,124C 'calendarinvit':50B,91C 'chosen':62B 'classic':38B,97C,141C 'code':162C 'collabor':7A,35B,76C 'collaboration':20A,24A,26A 'contain':121C 'context':149C 'craft':53B,123C 'cross':44B,83C 'cross-sit':43B,82C 'cve':12A,15A 'discov':4A,73C 'email':27B,58B,119C 'embed':128C 'execut':146C,158C 'exist':88C 'exploit':28B,115C 'featur':51B,92C 'flaw':47B 'handl':107C 'header':55B,111C,125C 'host':32B 'improp':102C 'input':103C 'interfac':40B,99C,142C 'issu':2A,71C 'javascript':63B,161C 'lead':156C 'messag':120C,136C 'packag':29B 'payload':130C,144C 'potenti':155C 'run':59B 'script':46B,85C 'self':31B 'self-host':30B 'session':69B,154C 'site':45B,84C 'suit':36B 'suite':21A 'synacor':18A 'user':98C 'valid':104C 'via':117C 'victim':66B,133C,152C 'view':134C 'vulner':87C 'webmail':39B,96C,140C 'xss':86C,129C 'zcs':8A,22A,77C 'zimbra':6A,19A,23A,25A,33B,34B,75C,95C,139C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2024-08-12T15:15:20+00:00","kev":{"dateAdded":"2025-05-19","dueDate":"2025-06-09","requiredAction":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2024-27443","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2024-27443","severity":null,"published_at":"2025-05-19T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T11:39:14+00:00","note":null},{"source":"nvd","external_id":"CVE-2024-27443","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-27443","severity":null,"published_at":"2024-08-12T15:15:20+00:00","modified_at":"2026-06-17T07:19:54+00:00","first_seen_at":"2026-10-23T22:29:05+00:00","fetched_at":"2026-10-23T22:29:05+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}