Vulnerability · Published Sep 21, 2026 · Assigned by GitHub_M

CVE-2026-76898draw.io: Unauthenticated SSRF via IPv6 ULA blocklist bypass in /embed2.js

High 7.7

In plain English

A high-severity server-side request forgery in drawio from jgraph. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 29% of all known vulnerabilities).

Severity (CVSS 4.0)7.7High

Exploit odds (30 days)0.4%top 71.1% 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 30.3.8, src/main/java/com/mxgraph/online/Utils.java checks IPv6 Unique Local Addresses in Utils.sanitizeUrl() by comparing the text prefixes fc00:: and fd00::, but the JDK returns the expanded address form, so the fc00::/7 range, including the AWS metadata range fd00:ec2::/32, is not blocked. An unauthenticated request to /embed2.js?fetch= can therefore make src/main/java/com/mxgraph/online/EmbedServlet2.java fetch an IPv6 ULA internal resource and reflect the response to the requester. Utils.validatedAddress() uses the same private-address check for the separate ProxyServlet path, which requires ENABLE_DRAWIO_PROXY=1. The primary /embed2.js path requires no proxy feature flag or DNS rebinding, and it can disclose cloud metadata credentials or data from other IPv6-reachable internal services. This issue is fixed in version 30.3.8.

Affected products (as reported)

Vendor	Product	Versions
jgraph	drawio	< 30.3.8

Weakness: CWE-918 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:N/SA:N

References

https://github.com/jgraph/drawio/security/advisories/GHSA-m3q9-cwfq-hcjc x_refsource_CONFIRM
https://github.com/jgraph/drawio/commit/73c4a91196246bbdb60f52b15871e82006b7972d x_refsource_MISC
https://github.com/jgraph/drawio/releases/tag/v30.3.8 x_refsource_MISC