XSS in Jgraph Drawio

CVE-2026-58504

draw.io is a configurable diagramming and whiteboarding application. Prior to version 30.2.5, opening or importing a crafted .drawio file can execute attacker-controlled JavaScript in the draw.io origin when selected cells are processed by TextFormatPanel.addFont() in src/main/webapp/js/grapheditor/Format.js. An HTML sibling cell keeps the formatted-label path enabled while an editable=0 plain-text sibling is excluded from the merged selection style but remains in the iteration set. graph.cellRenderer.getLabelValue() returns that plain-text label without HTML encoding, and mxUtils.canConvertHtmlToSvg() parses it as HTML, bypassing the earlier CVE-2026-46642 remediation. Successful exploitation can expose diagram data, browser storage, non-HttpOnly cookies, and same-origin actions available to the victim. This issue is fixed in version 30.2.5.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (16.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-58504: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-58504?
CVE-2026-58504 is a medium-severity vulnerability in Jgraph Drawio, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-09-21.
How severe is CVE-2026-58504?
Medium severity. CVSS v3 base score is 6.1 out of 10.