Discourse <2026.6.0 tag leakage via category endpoints (allowed_tags)
CVE-2026-49256 Published on July 9, 2026
Discourse: Hidden tag names leaked via category serializers
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.
Vulnerability Analysis
CVE-2026-49256 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
What is an Information Disclosure Vulnerability?
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
CVE-2026-49256 has been classified to as an Information Disclosure vulnerability or weakness.
Products Associated with CVE-2026-49256
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Affected Versions
discourse:- Version >= 2026.1.0-latest, < 2026.1.5 is affected.
- Version >= 2026.4.0-latest, < 2026.4.2 is affected.
- Version >= 2026.5.0-latest, < 2026.5.1 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.