CVE-2026-32951: Discourse: Authorization bypass in oneboxer via user-controlled category id

Severity: medium (CVSS 4.3 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: 2026-03-31 · updated 2026-07-24
Weakness: CWE-200

Description

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an authenticated user can obtain shared draft topic titles by sending an inline onebox request with a category_id parameter matching the shared drafts category. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Affected products

discourse: from 2026.1.0 before 2026.1.3; from 2026.2.0 before 2026.2.2; 2026.3.0 — fixed in 2026.1.3, 2026.2.2

How to fix

Upgrade to a fixed version: discourse 2026.1.3, 2026.2.2. Check the vendor advisory for mitigations.

References

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