CVE-2026-28282

Description

Discourse is an open-source discussion platform. Versions prior to 2026.3.0, 2026.2.1, and 2026.1.2 have a security flaw in the discourse-policy plugin which allowed a user with policy creation permission to gain membership access to any private/restricted groups. Once membership to a private/restricted group has been obtained, the user will be able to read private topics that only the group has access to. Versions 2026.3.0, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, review all policies for the use of `add-users-to-group` and temporarily remove the attribute from the policy. Alternatively, disable the discourse-policy plugin by disabling the `policy_enabled` site setting.

How to fix CVE-2026-28282

To remediate CVE-2026-28282, upgrade the affected package to a fixed version below.

—upgrade to 2026.1.2 or later

Is CVE-2026-28282 being exploited?

Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

>= 2026.1.0, < 2026.1.2, >= 2026.2.0, < 2026.2.1, >= 2026.3.0, < 2026.4.0

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 4.0	—	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X