CVE-2026-72730Network attack vectorHinoki check available

Stored XSS via innerHTML transcript username rendering

Published Aug 10, 2026 · Updated Aug 10, 2026

Stored XSS in the Discourse Rich Text Editor allows remote authenticated users to execute scripts through crafted chat transcripts. The editor assigns username quote metadata to a transcript header with innerHTML, turning embedded markup into executable DOM content. A victim must open the stored transcript in the Rich Text Editor; the script then runs in that user's browser context, affecting confidentiality and integrity.

CVSS severity8.7
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored XSS in the Discourse Rich Text Editor allows remote authenticated users to execute scripts through crafted chat transcripts. The editor assigns username quote metadata to a transcript header with innerHTML, turning embedded markup into executable DOM content. A victim must open the stored transcript in the Rich Text Editor; the script then runs in that user's browser context, affecting confidentiality and integrity.

The record

CVE
CVE-2026-72730
Published
Aug 10, 2026
Updated
Aug 10, 2026
Vendor
Discourse
Product
Discourse
Classifications
T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2026.1.6
  2. Affected versionversion=>= 2026.5.0-latest, < 2026.5.2
  3. Affected versionversion=>= 2026.6.0-latest, < 2026.6.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Discourse · Discourseversion=< 2026.1.6; version=>= 2026.5.0-latest, < 2026.5.2; version=>= 2026.6.0-latest, < 2026.6.1

Published CVSS scores

8.7GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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