CVE-2023-45806Network attack vector

Content duplication via unescaped display-name regular expressions

Published Nov 10, 2023 · Updated Sep 3, 2024

Regular expression denial of service in affected Discourse releases allows remote authenticated users to generate duplicate content in quoted posts. The quote-rewrite job interpolates the prior display name into regular expressions without escaping metacharacters, so an embedded | changes matching while substitutions rewrite raw and rendered quotes. Exploitation requires a quoted account with | in its full name to update that name, triggering duplicate content across posts that quoted the account.

CVSS severity4.3
Medium
EPSS probability1.00%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Regular expression denial of service in affected Discourse releases allows remote authenticated users to generate duplicate content in quoted posts. The quote-rewrite job interpolates the prior display name into regular expressions without escaping metacharacters, so an embedded | changes matching while substitutions rewrite raw and rendered quotes. Exploitation requires a quoted account with | in its full name to update that name, triggering duplicate content across posts that quoted the account.

The record

CVE
CVE-2023-45806
Published
Nov 10, 2023
Updated
Sep 3, 2024
Vendor
Discourse
Product
Discourse
Classifications
CWE-1333, T1499
Attack vector
network
Privileges
authenticated

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

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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=< 3.1.3
  2. Affected versionversion=>= 3.2.0.beta0, < 3.2.0.beta3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

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

Published CVSS scores

4.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L

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-1333Inefficient Regular Expression Complexity
T1499Endpoint Denial of Service

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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