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PatchSiren cyber security CVE debrief

CVE-2026-47264 discourse CVE debrief

CVE-2026-47264 is an information disclosure vulnerability in Discourse's DetailedTagSerializer. Versions 2026.1.0-latest to before 2026.1.4, 2026.3.0-latest to before 2026.3.1, and 2026.4.0-latest to before 2026.4.1 are affected. The vulnerability allows anonymous and unprivileged users to read the names of tag groups restricted to specific user groups or non-visible categories when SiteSetting.tags_listed_by_group is enabled.

Vendor
discourse
Product
Unknown
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-12
Original CVE updated
2026-06-17
Advisory published
2026-06-12
Advisory updated
2026-06-17

Who should care

Users of Discourse, especially those with SiteSetting.tags_listed_by_group enabled, should be aware of this vulnerability and take action to patch their installations.

Technical summary

The DetailedTagSerializer#tag_group_names method returned every tag group a tag belonged to without filtering against the requesting user's visibility. This allowed unauthorized access to sensitive information.

Defensive priority

MEDIUM

Recommended defensive actions

  • Upgrade to a patched version of Discourse (2026.1.4, 2026.3.1, 2026.4.1, or 2026.5.0-latest.1) to fix the vulnerability.

Evidence notes

The vulnerability was patched in versions 2026.1.4, 2026.3.1, 2026.4.1, and 2026.5.0-latest.1.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-47264 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-47264

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-47264 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-47264

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.