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CVE-2026-28282

Discourse vulnerable to group membership addition permission bypass via discourse-policy plugin

2.3 LowFix available

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 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-latest.1, 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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
None

Exploit likelihood

0.35%Up 0.3 points since Mar 20, 2026
90%50%10%1%

What each source reports

CVE List Score used 2.3

Discourse vulnerable to group membership addition permission bypass via discourse-policy plugin

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 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-latest.1, 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.

Record
CVE-2026-28282
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-863
Updated
2026-11-02
EUVDEUVD-2026-13243 2.3

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 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-latest.1, 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.

Record
EUVD-2026-13243
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Updated
2026-11-02
NVD 2.3

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 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-latest.1, 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.

Record
CVE-2026-28282
CVSS 4.0
2.3 LowCVSS: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
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-863
Updated
2026-11-02
OSV 2.3

Discourse vulnerable to group membership addition permission bypass via discourse-policy plugin

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 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-latest.1, 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.

Record
CVE-2026-28282
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-863
Updated
2026-11-02
OSVBIT-discourse-2026-28282 No score

Discourse vulnerable to group membership addition permission bypass via discourse-policy plugin

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.

Record
BIT-discourse-2026-28282
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
discourse
Bitnami
2026.1.0 up to 2026.1.2, 2026.2.0 up to 2026.2.1, 2026.3.0 up to 2026.4.0
2026.1.22026.2.12026.4.0

History

History
RecordedChangedSources
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-28282 is a low vulnerability (CVSS 2.3) in Discourse, published March 19, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.35%, the 29th percentile. Fixed in discourse 2026.1.2.

References

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