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Discourse CVE-2026-27152

LOW
Improper Access Control (CWE-284)
2026-02-26 security-advisories@github.com
3.8
CVSS 3.1 · GitHub Advisory
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2021 - Broken Access Control
ASVS 5.0
V4 - Access Control Authorization enforcement, RBAC validation
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS 3.8 (LOW). Attack vector: Network. Complexity: Low. Privileges required: High. User interaction: None.

Exploit ScenarioDerived

An attacker could exploit this vulnerability to compromise the affected system.

Monitor Track and reassess. Why: LOW severity (CVSS 0.1-3.9).
No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Discourse is an open source discussion platform. [CVSS 3.8 LOW]

RemediationAI

Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Classified as CWE-284 (Improper Access Control). Affects Discourse. Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, DM communication-preference bypass when adding members via Chat::AddUsersToChannel — a user could add targets who have blocked/ignored/muted them to an existing DM channel, bypassing per-recipient PM restrictions that are enforced during DM channel creation. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 3.8 LOW
AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

DescriptionGitHub Advisory

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, DM communication-preference bypass when adding members via Chat::AddUsersToChannel - a user could add targets who have blocked/ignored/muted them to an existing DM channel, bypassing per-recipient PM restrictions that are enforced during DM channel creation. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.

Executive ViewAI

Why It Matters

CVE-2026-27152 is a low-severity vulnerability in Discourse involving access control (CVSS 3.8). The limited severity suggests constrained impact, typically requiring specific conditions or local access for exploitation. Apply vendor updates when available as part of routine maintenance.

Business Impact: Low
Compensating Controls

Apply vendor patch during routine maintenance. Standard access control mitigations apply if patching is delayed.

Threat Intelligence Overview

EPSS Score
0.0%
Top 93% exploitable
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity LOW
CISA KEV No
Public POC No
EPSS 0.0%
Patch available No
Active threat No
Deciding rule
LOW severity (CVSS 0.1-3.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact
Low

Priority Score

19
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +19
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Affected Products (CPE)GitHub Advisory

cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
cpe:2.3:a:discourse:discourse:2026.2.0:*:*:*:latest:*:*:*
CVE-2025-48954 HIGH POC
8.1 Jun 25

Discourse versions prior to 3.5.0.beta6 contain a reflected cross-site scripting (XSS) vulnerability in social login fun

CVE-2022-46162 CRITICAL POC
9.8 Nov 30

discourse-bbcode is the official BBCode plugin for Discourse. Rated critical severity (CVSS 9.8), this vulnerability is

CVE-2026-27934 HIGH POC
8.7 Mar 19

Unauthorized information disclosure in Discourse discussion platform versions prior to 2026.3.0-latest.1, 2026.2.1, and

CVE-2024-47773 HIGH POC
8.2 Oct 08

Discourse is an open source platform for community discussion. Rated high severity (CVSS 8.2), this vulnerability is rem

CVE-2026-26265 HIGH POC
7.5 Feb 26

Discourse versions prior to 2025.12.2, 2026.1.1, and 2026.2.0 contain an insecure direct object reference (IDOR) in the

CVE-2021-3138 HIGH POC
7.5 Jan 14

In Discourse 2.7.0 through beta1, a rate-limit bypass leads to a bypass of the 2FA requirement for certain forms. Rated

CVE-2026-26077 MEDIUM POC
6.5 Feb 26

Unauthenticated attackers can submit forged webhook payloads to multiple email provider integrations in Discourse versio

CVE-2023-38706 MEDIUM POC
6.5 Sep 15

Discourse is an open-source discussion platform. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploi

CVE-2024-53991 MEDIUM POC
5.9 Dec 19

Discourse is an open source platform for community discussion. Rated medium severity (CVSS 5.9), this vulnerability is r

CVE-2025-48877 CRITICAL
9.8 Jun 09

Discourse versions prior to 3.4.4 (stable), 3.5.0.beta5 (beta), and 3.5.0.beta6-dev (tests-passed) contain a critical vu

CVE-2023-47121 CRITICAL
9.8 Nov 10

Discourse is an open source platform for community discussion. Rated critical severity (CVSS 9.8), this vulnerability is

CVE-2022-39355 CRITICAL
9.8 Oct 26

Discourse Patreon enables syncronization between Discourse Groups and Patreon rewards. Rated critical severity (CVSS 9.8

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