# Roundcube Webmail: Insufficient CSS sanitization in HTML e-mail messages

Advisory record · `GHSA-xpqh-grpw-4xmg`

- **Identifiers:** `GHSA-xpqh-grpw-4xmg` · `CVE-2026-35544` · `PKSA-wvxn-8qzx-v8n9`
- **State:** Confirmed
- **Severity:** CVSS 5.3 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-669](https://cwe.mitre.org/data/definitions/669.html)
- **Tags:** [CWE-669](https://agentprime.io/advisories/tag/cwe-669.md)
- **Published:** 3 Apr 2026
- **Updated:** 4 Apr 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 3 Apr 2026, 06:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `roundcube/roundcubemail` (Packagist): affected `>=1.7-beta, <1.7-rc5`; fixed in `1.7-rc5`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Roundcube Webmail from 1.7-beta before 1.7-rc5 is affected, according to the package record. Insufficient CSS sanitization in HTML e-mail messages allows a fixed-position mitigation to be bypassed using !important, and the source gives few details on the impact. Upgrade to 1.7-rc5; the description also lists 1.5.14 and 1.6.14 as fixes for earlier branches.

Written 3 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.3 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`, from CNA (mitre)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0038, the 32nd percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:25 UTC: First seen by agentprime
- 31 Oct 2026, 14:25 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-xpqh-grpw-4xmg)

## Sources

- [GitHub Advisory Database: GHSA-xpqh-grpw-4xmg](https://github.com/advisories/GHSA-xpqh-grpw-4xmg)
- [OSV: GHSA-xpqh-grpw-4xmg](https://osv.dev/vulnerability/GHSA-xpqh-grpw-4xmg)
- <https://nvd.nist.gov/vuln/detail/CVE-2026-35544>
- <https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662>
- <https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0>
- <https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7>
- <https://github.com/roundcube/roundcubemail>
- <https://github.com/roundcube/roundcubemail/releases/tag/1.5.14>
- <https://github.com/roundcube/roundcubemail/releases/tag/1.6.14>
- <https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5>
- <https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-xpqh-grpw-4xmg>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-xpqh-grpw-4xmg/>. Everything for agents: <https://agentprime.io/llms.txt>.