Discourse
CVE-2026-33423
LOW
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/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
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/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
Lifecycle Timeline
2DescriptionGitHub Advisory
Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, staff can modify any user's group notification level. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.
AnalysisAI
A privilege escalation vulnerability in Discourse allows staff members to arbitrarily modify group notification levels for any user without proper authorization checks. This affects Discourse versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, enabling authenticated staff users to alter notification settings for other users in ways they should not be permitted to do. …
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Vulnerability AssessmentAI
| Risk Assessment | The risk assessment is complicated by the absence of CVSS and EPSS scores, but several contextual factors indicate moderate-to-high priority. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | A moderator or staff member with legitimate group management permissions logs into the Discourse instance and navigates to the group notification settings interface. Instead of only modifying notification levels for their intended group or purpose, they exploit the missing authorization checks to modify notification levels for arbitrary users across other groups, potentially silencing critical notifications that those users should receive or escalating notification frequency to cause harassment. … |
| Remediation | Organizations running Discourse should immediately upgrade to version 2026.3.0-latest.1, 2026.2.1, or 2026.1.2 or later depending on their current version line, as patches are available for all affected versions and no workarounds are documented. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
During next maintenance window: Apply vendor patches when convenient. …
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External POC / Exploit Code
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