CVE-2023-25172Network attack vector

Stored XSS via unnormalized local-onebox URL

Published Mar 17, 2023 · Updated Feb 25, 2025

Stored XSS in Discourse stable before 3.0.1 allows remote authenticated users to execute script through a crafted full-name URL. The local-onebox renderer interpolates the URL into link and media-source HTML without output normalization. Beta and tests-passed before 3.1.0.beta2 are also affected; execution requires a victim to view the post and a disabled or permissive CSP.

CVSS severity4.4
Medium
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Discourse stable before 3.0.1 allows remote authenticated users to execute script through a crafted full-name URL. The local-onebox renderer interpolates the URL into link and media-source HTML without output normalization. Beta and tests-passed before 3.1.0.beta2 are also affected; execution requires a victim to view the post and a disabled or permissive CSP.

The record

CVE
CVE-2023-25172
Published
Mar 17, 2023
Updated
Feb 25, 2025
Vendor
Discourse
Product
Discourse
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2025Record 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=beta < 3.1.0.beta2
  2. Affected versionversion=stable < 3.0.1
  3. Affected versionversion=tests-passed < 3.1.0.beta2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Discourse · Discourseversion=beta < 3.1.0.beta2; version=stable < 3.0.1; version=tests-passed < 3.1.0.beta2

Published CVSS scores

4.4GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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 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

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
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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