Vulnerability · Published Sep 21, 2026 · Assigned by GitHub_M

CVE-2026-58504draw.io: Stored XSS on file open via editable=0 sibling cell — patch bypass of CVE-2026-46642

Medium 6.1

In plain English

A medium-severity cross-site scripting in drawio from jgraph. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities).

Severity (CVSS 3.1)6.1Medium

Exploit odds (30 days)0.2%top 83.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
jgraph	drawio	< 30.2.5

Weakness: CWE-79, CWE-116 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

https://github.com/jgraph/drawio/security/advisories/GHSA-c76x-r78m-phwx x_refsource_CONFIRM
https://github.com/jgraph/drawio/commit/7976c02e1b10b1687c028d82782f9f5d90a885d6 x_refsource_MISC
https://github.com/jgraph/drawio/releases/tag/v30.2.5 x_refsource_MISC