# CVE-2025-48700: Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting

> Attackers can execute arbitrary JavaScript in Zimbra Classic UI via crafted emails, potentially stealing sensitive data or taking over accounts.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Yes, since 20 Apr 2026 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 23 Jun 2025
- **Updated:** 21 Apr 2026
- **Also known as:** GHSA-wmq6-ffv7-gqwf

## What is CVE-2025-48700?

CVE-2025-48700 is a medium-severity cross-site scripting vulnerability in Synacor Zimbra Collaboration Suite, published on 23 Jun 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2025-48700?

It affects 1 product.


Products: Synacor Zimbra Collaboration Suite.

## How do I fix CVE-2025-48700?

No fix has been published for CVE-2025-48700 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 23 Apr 2026.

## Is CVE-2025-48700 being exploited?

Yes. Attackers have exploited CVE-2025-48700 in the wild since at least 20 Apr 2026.

## Other vulnerabilities in Synacor Zimbra Collaboration Suite

- [CVE-2024-45519](https://insights.sbomify.com/CVE-2024-45519/): Synacor Zimbra Collaboration Suite (ZCS) Command Execution (critical 10.0, exploited in the wild)
- [CVE-2022-41352](https://insights.sbomify.com/CVE-2022-41352/): Synacor Zimbra Collaboration Suite (ZCS) Arbitrary File Upload (critical 9.8, exploited in the wild)
- [CVE-2022-37042](https://insights.sbomify.com/CVE-2022-37042/): Synacor Zimbra Collaboration Suite (ZCS) Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2022-27924](https://insights.sbomify.com/CVE-2022-27924/): Synacor Zimbra Collaboration Suite (ZCS) Command Injection (critical 9.8, exploited in the wild)
- [CVE-2020-7796](https://insights.sbomify.com/CVE-2020-7796/): Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-48700 and fix it if it is affected.

What it is: CVE-2025-48700 is a medium-severity cross-site scripting vulnerability in Synacor Zimbra Collaboration Suite, published on 23 Jun 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: Yes. Attackers have exploited CVE-2025-48700 in the wild since at least 20 Apr 2026.

Affected product: Synacor Zimbra Collaboration Suite. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-48700/ (Markdown: https://insights.sbomify.com/CVE-2025-48700/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-48700
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-48700
- OSV: https://osv.dev/vulnerability/CVE-2025-48700

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-48700/
Summaries are generated and may contain mistakes; the official description above is the record.