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. 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 (github)
Affected products and versions
- 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.
Sources
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on .