CVE-2026-33393

MEDIUM
2026-03-19 [email protected]
4.3
CVSS 3.1
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CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

Lifecycle Timeline

2
Analysis Generated
Mar 19, 2026 - 22:30 vuln.today
CVE Published
Mar 19, 2026 - 22:16 nvd
MEDIUM 4.3

Tags

Authentication Bypass

Description

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the `allowed_spam_host_domains` check used `String#end_with?` without domain boundary validation, allowing domains like `attacker-example.com` to bypass spam protection when `example.com` was allowlisted. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 require exact match or proper subdomain match (preceded by `.`) to prevent suffix-based bypass of `newuser_spam_host_threshold`. No known workarounds are available.

Analysis

A remote code execution vulnerability in Discourse (CVSS 4.3). Remediation should follow standard vulnerability management procedures.

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Remediation

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.

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Priority Score

22
Low Medium High Critical
KEV: 0
EPSS: +0.0
CVSS: +22
POC: 0

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CVE-2026-33393 vulnerability details – vuln.today
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