What’s Vulnerable › Vulnerabilities

CVE-2026-33355: Discourse filters whisper posts from private-posts feed

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-19 · updated 2026-06-17
• Weakness: CWE-200

Description

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the `/private-posts` endpoint did not apply post-type visibility filtering, allowing regular PM participants to see whisper posts in PM topics they had access to. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Affected products

• discourse: from 2026.1.0 before 2026.1.2; from 2026.2.0 before 2026.2.1; 2026.3.0 — fixed in 2026.1.2, 2026.2.1

How to fix

Upgrade to a fixed version: discourse 2026.1.2, 2026.2.1. Check the vendor advisory for mitigations.

References

• https://github.com/discourse/discourse/commit/84e5865a279716c6866e8c0648d1d8b42320603c
• https://github.com/discourse/discourse/commit/d25b8ee9ee182dbb34e92b34e39878ce4d59bcdc
• https://github.com/discourse/discourse/commit/d2f317271ad7638f1e2791905472ebd9370946d1
• https://github.com/discourse/discourse/security/advisories/GHSA-g4v5-6gfp-3hjq

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