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CVE-2026-76898

draw.io: Unauthenticated SSRF via IPv6 ULA blocklist bypass in /embed2.js

HIGH
7.7
CVSS Score
Published: September 21, 2026 at 04:31 PM UTC
Updated: September 24, 2026 at 11:18 PM UTC
1 product affected across 1 vendorDrawio

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Severity
HIGH7.7
Exploit prediction
EPSS 0.4%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Drawio· Jgraph
60%
v < 30.3.8
Affected range stops below 30.3.8, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (3)

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

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.7HIGHGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-918

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