High severity · published Jul 9, 2026
CVE-2026-49256
Discourse: Hidden tag names leaked via category serializers
7.5
CVSS
0.5%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DI
discourse · discourse
>= 2026.1.0-latest, < 2026.1.5; >= 2026.4.0-latest, < 2026.4.2; >= 2026.5.0-latest, < 2026.5.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-49256
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-49256
Release Notes
https://github.com/discourse/discourse/releases/tag/v2026.1.5
Release Notes
https://github.com/discourse/discourse/releases/tag/v2026.4.2
Release Notes
https://github.com/discourse/discourse/releases/tag/v2026.5.1
Release Notes
https://github.com/discourse/discourse/releases/tag/v2026.6.0
Vendor Advisory
https://github.com/discourse/discourse/security/advisories/GHSA-mwp7-572g-6qpx
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