CVE-2023-47119Network attack vector

HTML injection via unescaped Onebox templates

Published Nov 10, 2023 · Updated Sep 3, 2024

HTML injection in Discourse before 3.1.3 stable and 3.2.0.beta3 beta allows remote attackers to inject arbitrary tags through Onebox. Onebox Mustache templates render category names, descriptions, colors, and chat channel names with unescaped triple-curlies, while GitHub label names reach a template without HTML escaping. A crafted link must be Oneboxed; injected markup can alter rendered forum content or hide page elements, with no demonstrated script execution.

CVSS severity5.3
Medium
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

HTML injection in Discourse before 3.1.3 stable and 3.2.0.beta3 beta allows remote attackers to inject arbitrary tags through Onebox. Onebox Mustache templates render category names, descriptions, colors, and chat channel names with unescaped triple-curlies, while GitHub label names reach a template without HTML escaping. A crafted link must be Oneboxed; injected markup can alter rendered forum content or hide page elements, with no demonstrated script execution.

The record

CVE
CVE-2023-47119
Published
Nov 10, 2023
Updated
Sep 3, 2024
Vendor
Discourse
Product
Discourse
Classifications
CWE-74, CWE-79, T1491.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <3.1.3
  2. Affected versionversion=< 3.1.3
  3. Affected versionversion=>= 3.2.0.beta0, < 3.2.0.beta3
  4. Affected versionversion=3.2.0.beta0 <3.2.0.beta3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Discourse · Discourseversion=0 <3.1.3; version=< 3.1.3; version=>= 3.2.0.beta0, < 3.2.0.beta3; version=3.2.0.beta0 <3.2.0.beta3

Published CVSS scores

5.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
6.1NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1491.002External Defacement

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo