CVE-2026-33355
Information Disclosure in Discourse /private-posts Endpoint via Visibility Bypass
Publication date: 2026-03-19
Last updated on: 2026-03-24
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| discourse | discourse | From 2026.1.0 (inc) to 2026.1.2 (exc) |
| discourse | discourse | From 2026.2.0 (inc) to 2026.2.1 (exc) |
| discourse | discourse | 2026.3.0 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-200 | The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in the Discourse open-source discussion platform prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2. The issue is that the `/private-posts` endpoint did not properly apply post-type visibility filtering. As a result, regular private message (PM) participants could see whisper posts within PM topics they had access to, even though those whisper posts were intended to be hidden.
How can this vulnerability impact me? :
The impact of this vulnerability is that unauthorized users who are regular participants in private message topics could view sensitive whisper posts that were meant to be hidden. This leads to a confidentiality breach where private or sensitive information could be exposed to unintended recipients.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should upgrade your Discourse installation to one of the patched versions: 2026.3.0-latest.1, 2026.2.1, or 2026.1.2.
No known workarounds are available, so applying the patch by upgrading is the recommended immediate step.