CVE-2023-23621 - CVE House

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Status published High CVE-2023-23621

Discourse vulnerable to ReDoS in user agent parsing

8.6 CVSS

Vulnerability Description

Discourse is an open-source discussion platform. Prior to version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches. There are no known workarounds.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

More from discourse

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Discourse has insecure default configuration that allows non-admin moderators to takeover any non-staff account via email change

Discourse moderators can access admin-only reports exposing private upload URLs

Discourse Has Denial of Service (DoS) Vulnerability in Drafts Creation Endpoint

Discourse non-admin moderators can exfiltrate private content via post ownership transfer

Discourse users archives leaked to users with moderation privileges

Affected Vendor

discourse

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Affected Software

discourse

Vulnerable Versions:

< 3.0.1, = 3.1.0.beta1

Timeline

Official Publish: January 27th, 2023

Last Modified: March 10th, 2025

Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Weaknesses (CWE)

MITRE ATT&CK TTPs

T1499 Endpoint Denial of Service

T1190 Exploit Public-Facing Application

T1496 Resource Hijacking

T1562 Impair Defenses

Defense Evasion

T1070 Indicator Removal on Host

Defense Evasion