Discourse up to 2025.12.1/2026.1.0 Chat::AddUsersToChannel access control

CVSS Meta Temp Score
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CTI Interest Score
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4.9$0-$5k0.00

Summaryinfo

A vulnerability was found in Discourse up to 2025.12.1/2026.1.0. It has been classified as critical. This affects the function Chat::AddUsersToChannel. The manipulation leads to access control. This vulnerability is traded as CVE-2026-27152. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Discourse up to 2025.12.1/2026.1.0. This issue affects the function Chat::AddUsersToChannel. The manipulation with an unknown input leads to a access control vulnerability. Using CWE to declare the problem leads to CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-27152 since 02/18/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

Upgrading to version 2025.12.2, 2026.1.1 or 2026.2.0 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 4.9

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 3.8
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Discourse 2025.12.2/2026.1.1/2026.2.0

Timelineinfo

02/18/2026 CVE reserved
02/26/2026 +8 days Advisory disclosed
02/26/2026 +0 days VulDB entry created
03/03/2026 +5 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-27152 (🔒)
GCVE (CVE): GCVE-0-2026-27152
GCVE (VulDB): GCVE-100-348059

Entryinfo

Created: 02/26/2026 22:19
Updated: 03/03/2026 12:17
Changes: 02/26/2026 22:19 (68), 03/03/2026 12:17 (13)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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