CVE-2026-76898 draw.io: Unauthenticated SSRF via IPv6 ULA blocklist bypass in /embed2.js
Unauthenticated attackers can bypass IPv6 blocklists to fetch internal resources and cloud metadata via the embed endpoint.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-76898?
CVE-2026-76898 is a high-severity server-side request forgery vulnerability in jgraph drawio, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-918
Which versions are affected by CVE-2026-76898?
How do I fix CVE-2026-76898?
No fix has been published for CVE-2026-76898 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-76898 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-76898 exists.
Sources
Also known as GHSA-m3q9-cwfq-hcjc.