CVE-2026-49256

Discourse: Hidden tag names leaked via category serializers

CVSS 6.3 MEDIUMCWE-200

Vexday Risk Score

10Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 6.3EPSS —KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

09 Jul 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, restricted tag and tag-group names attached to publicly readable categories as allowed_tags, allowed_tag_groups, or required tag groups could leak to anonymous and unauthorized users through category and group endpoints. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Affected products

discourse · discourse

References

https://github.com/discourse/discourse/releases/tag/v2026.1.5 https://github.com/discourse/discourse/releases/tag/v2026.4.2 https://github.com/discourse/discourse/releases/tag/v2026.5.1 https://github.com/discourse/discourse/releases/tag/v2026.6.0 https://github.com/discourse/discourse/security/advisories/GHSA-mwp7-572g-6qpx