{"basis":"claimed","id":"CVE-2025-48700","name":"Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability","vendorProject":"Synacor","product":"Zimbra Collaboration Suite (ZCS)","publishedAt":"2025-06-23","cvss":{"score":6.1,"severity":"MEDIUM","version":"3.1"},"exploited":{"kevAdded":"2026-04-20","dueDate":"2026-04-23","ransomware":false},"epss":{"score":0.01713,"percentile":0.77383,"date":"2026-11-02"},"coverage":{"cloudflare":{"status":"none","firstOn":null,"daysToRule":null},"aws":{"status":"none","firstOn":null,"daysToRule":null},"azure":{"status":"none","firstOn":null,"daysToRule":null},"google":{"status":"none","firstOn":null,"daysToRule":null},"fastly":{"status":"no_history","firstOn":null,"daysToRule":null},"f5":{"status":"none","firstOn":null,"daysToRule":null},"akamai":{"status":"no_source","firstOn":null,"daysToRule":null},"crs":{"status":"none","firstOn":null,"daysToRule":null}},"title":null,"description":"An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0 and 10.1. A Cross-Site Scripting (XSS) vulnerability in the Zimbra Classic UI allows attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information. This issue arises from insufficient sanitization of HTML content, specifically involving crafted tag structures and attribute values that include an @import directive and other script injection vectors. The vulnerability is triggered when a user views a crafted e-mail message in the Classic UI, requiring no additional user interaction.","cwes":["CWE-79"],"vendors":[{"vendor":"cloudflare","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"aws","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"azure","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"google","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"fastly","status":"no_history","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"f5","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"akamai","status":"no_source","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"crs","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]}],"updatedAt":"2026-11-04T03:17:38.044Z","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","ssvc":{"exploitation":"active","automatable":"no","technicalImpact":"partial"},"kevAction":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","kevNotes":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories ; https://nvd.nist.gov/vuln/detail/CVE-2025-48700","references":[{"url":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories","name":null,"tags":[]},{"url":"https://wiki.zimbra.com/wiki/Security_Center","name":null,"tags":[]},{"url":"https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy","name":null,"tags":[]}],"affected":[],"briefing":{"status":{"id":"known_exploited","label":"Known exploited"},"why":"CISA lists CVE-2025-48700 as exploited in the wild since 2026-04-20. It is reachable over the network without credentials (CVSS 6.1). No edge WAF vendor names it in a changelog, so default managed rules may or may not catch it.","who":"Teams running Synacor Zimbra Collaboration Suite (ZCS). Affected versions are in the vendor advisory. Prioritise internet-facing instances.","what_to_do":[{"text":"Find the version you run. On the Zimbra server:","command":{"where":"On the Zimbra server","command":"su - zimbra -c 'zmcontrol -v'"}},{"text":"Apply the vendor's fix; the advisory lists the affected and fixed versions.","href":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories","linkText":"wiki.zimbra.com"},{"text":"CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. US federal agencies must act by 2026-04-23."},{"text":"Review exposed instances for signs of compromise: it was exploited before many systems were patched, and a later patch does not undo access already gained."},{"text":"Do not rely on WAF defaults: no edge vendor names this CVE. Restrict access to the vulnerable component or add a custom rule until it is patched.","href":"#edge","linkText":"Edge coverage"},{"text":"Check which WAF sits in front of your site and whether it covers this CVE.","href":"#check","linkText":"Check your domain"}],"evidence":[{"heading":"CVE record","text":"CVSS 3.1 6.1 (medium). Weakness: CWE-79.","links":[{"label":"CVE-2025-48700","href":"https://www.cve.org/CVERecord?id=CVE-2025-48700"},{"label":"NVD","href":"https://nvd.nist.gov/vuln/detail/CVE-2025-48700"}]},{"heading":"Vendor advisory","text":"Fixes and mitigations the CVE record links to. Check affected builds against the vendor, including backports.","links":[{"label":"wiki.zimbra.com","href":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories"}]},{"heading":"Exploit evidence","text":"No public exploit code found in Exploit-DB, Metasploit, nuclei-templates or GitHub. That does not mean none exists.","links":[]},{"heading":"Seen exploited","text":"Claimed in 2 Telegram posts (unverified).","links":[]},{"heading":"CISA KEV","text":"Added 2026-04-20, federal due date 2026-04-23 (catalog 2026.11.03, checked 2026-11-04).","links":[{"label":"CISA KEV catalog","href":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2025-48700"}]},{"heading":"EPSS","text":"1.71% probability of exploitation activity in the next 30 days, higher than 77% of CVEs (2026-11-02).","links":[{"label":"FIRST EPSS","href":"https://api.first.org/data/v1/epss?cve=CVE-2025-48700"}]},{"heading":"WAF vendor statements","text":"No edge vendor changelog names it.","links":[]}],"agent_prompt":"Assess whether the infrastructure available to you is affected by CVE-2025-48700 (Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability). Perform a read-only assessment within your authorized access. Do not send exploit traffic, scan third-party systems, change configuration or restart services.\n\n1. Verify the CVE record at https://www.cve.org/CVERecord?id=CVE-2025-48700 and the vendor advisory. Establish affected and fixed versions, including vendor backports. Cite sources and retrieval dates; flag anything you cannot verify.\n2. Inventory deployments of Synacor Zimbra Collaboration Suite (ZCS): asset, environment, owner where known, installed version or build, and how you confirmed it (package metadata, a version endpoint, image tags), e.g. `su - zimbra -c 'zmcontrol -v'` (on the Zimbra server). An image tag alone does not prove the running version.\n3. Identify which deployments are reachable from the internet or untrusted networks, and through which paths (direct origin, load balancer, CDN or WAF).\n4. Assess compensating controls separately from patch status. Current edge WAF coverage for this CVE: no edge WAF vendor names it. Live data: https://cve.vigilbase.com/api/v1/cves/CVE-2025-48700. Check whether the rule is enabled and in block mode on each path, and whether any path bypasses the WAF. A WAF rule is not a patch.\n5. It is known exploited (CISA KEV): review logs on exposed instances for signs of exploitation before and after patching.\n\nReturn a short summary and a table: asset | version/build | assessment (affected, fixed, not applicable, unknown) | exposure | compensating control | evidence | next action. List what you could not assess and the access needed to resolve it. Do not infer absence of compromise from patch status or a lack of alerts.\n\nRemediation guidance: Apply the vendor's fix; the advisory lists the affected and fixed versions. CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. US federal agencies must act by 2026-04-23.\nMore: https://cve.vigilbase.com/cve/CVE-2025-48700"},"measured":[],"sightings":{"honeypot":null,"catalog":null,"reports":[],"telegram":{"posts":2,"last":"2026-08-19"},"days":{"honeypot":[],"reports":[],"telegram":["2026-08-06","2026-08-19"]}},"social":{"total":0,"first_seen":null,"daily":[{"day":"2026-10-22","posts":0},{"day":"2026-10-23","posts":0},{"day":"2026-10-24","posts":0},{"day":"2026-10-25","posts":0},{"day":"2026-10-26","posts":0},{"day":"2026-10-27","posts":0},{"day":"2026-10-28","posts":0},{"day":"2026-10-29","posts":0},{"day":"2026-10-30","posts":0},{"day":"2026-10-31","posts":0},{"day":"2026-11-01","posts":0},{"day":"2026-11-02","posts":0},{"day":"2026-11-03","posts":0},{"day":"2026-11-04","posts":0}],"top_posts":[],"exploit_repositories":[]}}