CVE-2023-43657Network attack vector

Cross-site scripting via unescaped decrypted topic titles

Published Sep 28, 2023 · Updated Sep 23, 2024

Cross-site scripting in Discourse Encrypt through c492904c allows attackers to execute script via encrypted topic titles. The decrypt-topics initializer assigns a decrypted, attacker-controlled title directly to the model's fancy_title field without HTML escaping. Exploitation requires an encrypted topic to be viewed on a site with CSP headers disabled, a non-default setting; script runs in the viewer's Discourse origin.

CVSS severity7.2
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Discourse Encrypt through c492904c allows attackers to execute script via encrypted topic titles. The decrypt-topics initializer assigns a decrypted, attacker-controlled title directly to the model's fancy_title field without HTML escaping. Exploitation requires an encrypted topic to be viewed on a site with CSP headers disabled, a non-default setting; script runs in the viewer's Discourse origin.

The record

CVE
CVE-2023-43657
Published
Sep 28, 2023
Updated
Sep 23, 2024
Vendor
Discourse
Product
Discourse Encrypt
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 23, 2024Record 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=0 <=c492904c
  2. Affected versionversion=<= c492904c

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Discourse · Discourse Encryptversion=0 <=c492904c; version=<= c492904c

Published CVSS scores

7.2GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
6.1NIST National Vulnerability DatabaseCVSS: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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

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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