# CVE-2026-54433 — Roundcube Webmail

> As of 2026-07-15, CVE-2026-54433 is a HIGH-severity vulnerability in Roundcube Webmail, CVSS v3.1 7.2, EPSS 0.3% (22.0th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-54433, most recently “Roundcube Webmail 0-Click Stored XSS (CVE-2026-54432, CVE-2026-54433) — Versions Prior to 1.6.17 / 1.7.2”.

**Last updated:** 2026-07-15

## What is CVE-2026-54433?

In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, there is Stored Cross-Site Scripting (XSS) via a crafted plain-text email message. The attacker-controlled JavaScript executes within the victim's authenticated session simply by opening or previewing the message (zero-click).

The record classifies CVE-2026-54433 under weakness class [CWE-79](https://intel.threadlinqs.com/cwe/CWE-79). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 106 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.2 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N`)
- **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 22.0% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 6.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-14, last modified 2026-07-15

## Is CVE-2026-54433 being exploited?

Weaponised exploit code for CVE-2026-54433 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 27 in the Threadlinqs vulnerability feed.

- [aramosf/CVE-2026-54433](https://github.com/aramosf/CVE-2026-54433) (github)

## Affected products and versions

- [Roundcube](https://intel.threadlinqs.com/vendors/roundcube): Webmail

## How to fix CVE-2026-54433

No vendor patch reference has been recorded for CVE-2026-54433 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-54433

1 tracked threat in the Threadlinqs corpus references CVE-2026-54433, either in the campaign’s CVE list or as an indicator on the campaign record.

- [Roundcube Webmail 0-Click Stored XSS (CVE-2026-54432, CVE-2026-54433) — Versions Prior to 1.6.17 / 1.7.2](https://intel.threadlinqs.com/threat/TL-2026-1185) — HIGH · 2026-07-10

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-10-10.

**Other references**

- [roundcube.net](https://roundcube.net/news/2026/07/05/security-updates-1.6.17-and-1.7.2)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-54433
Full detection coverage and IOCs for threats exploiting CVE-2026-54433 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp