CVE-2023-25167Network attack vector

Service hang via ambiguous SSH URL regex

Published Feb 8, 2023 · Updated Mar 10, 2025

ReDoS in Discourse before 3.0.1 and 3.1.0.beta through 3.1.0.beta1 allows remote authenticated users to hang the service via a crafted git URL. GitUrl.normalize applies SSH_REGEXP with ambiguous nested repetition to attacker-controlled SSH-style URLs, causing excessive regular-expression backtracking. Access to theme installation is required; exploitation consumes CPU and affects availability without reported data access or modification.

CVSS severity6.5
Medium
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

ReDoS in Discourse before 3.0.1 and 3.1.0.beta through 3.1.0.beta1 allows remote authenticated users to hang the service via a crafted git URL. GitUrl.normalize applies SSH_REGEXP with ambiguous nested repetition to attacker-controlled SSH-style URLs, causing excessive regular-expression backtracking. Access to theme installation is required; exploitation consumes CPU and affects availability without reported data access or modification.

The record

CVE
CVE-2023-25167
Published
Feb 8, 2023
Updated
Mar 10, 2025
Vendor
Discourse
Product
Discourse
Classifications
CWE-1333, T1499.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 8, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 10, 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=< 3.0.1
  2. Affected versionversion=>= 3.1.0.beta, < 3.1.0.beta2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Discourse · Discourseversion=< 3.0.1; version=>= 3.1.0.beta, < 3.1.0.beta2

Published CVSS scores

6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.7NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
T1499.003Application Exhaustion Flood

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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