CVE-2025-48700An 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…
- 6.1MediumCVSS base score
- 1.7%Exploitation in 30 daysEPSS · top 22% of all CVEs
- YesKnown exploitedin CISA's KEV since 20 Apr 2026
- YesPublic exploitsa reference or SSVC says so
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.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability.
- Added
- 20 Apr 2026
- Fix due (US federal)
- 23 Apr 2026
- Used by ransomware
- Not known
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 20 Apr 2026.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By mitre
- 31 days later
· 31 days later
Published
- 10 months later
· 10 months later
Added to CISA KEV
Known exploited in the wild
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Medium6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVDNVD · Analyzed | 3.1 | Medium6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 1.7% · top 22% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.1.
Affected products
n/a
- affected n/a
References
References4
- https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories (opens in a new tab)
- https://wiki.zimbra.com/wiki/Security_Center (opens in a new tab)
- https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy (opens in a new tab)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-48700 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-18891 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-48700)Record last updated .