CVE-2026-27152: DIscourse has DM communication-preference bypass when adding members

Severity: low (CVSS 3.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-26 · updated 2026-06-17
Weakness: CWE-284

Description

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.

Affected products

discourse: before 2025.12.2; from 2026.1.0 before 2026.1.1; 2026.2.0 — fixed in 2025.12.2, 2026.1.1

How to fix

Upgrade to a fixed version: discourse 2025.12.2, 2026.1.1. Check the vendor advisory for mitigations.

References

https://github.com/discourse/discourse/security/advisories/GHSA-f8ff-pxg3-7967

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