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CVE-2026-27481 discourse CVE debrief

CVE-2026-27481 is an authorization bypass vulnerability in Discourse, an open-source discussion platform. The vulnerability affects 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. It allows unauthenticated or unauthorized users to view hidden (staff-only) tags and its associated data. All Discourse instances with tagging enabled and staff-only tag groups configured are impacted. The issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Vendor
discourse
Product
Unknown
CVSS
MEDIUM 6.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-03
Original CVE updated
2026-07-24
Advisory published
2026-04-03
Advisory updated
2026-07-24

Who should care

Administrators and users of Discourse instances with tagging enabled and staff-only tag groups configured should be aware of this vulnerability and take necessary actions to patch their instances. This includes reviewing tagging configurations, monitoring for unauthorized access, and applying patches.

Technical summary

The vulnerability is caused by an authorization bypass issue in Discourse, an open-source discussion platform, allowing unauthenticated or unauthorized users to view hidden tags and associated data. This issue affects Discourse 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. All Discourse instances with tagging enabled and staff-only tag groups configured are impacted. The issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0. Administrators should review tagging configurations, monitor for unauthorized access, and apply patches. Evidence is limited to public CVE and NVD information, and instances should verify configurations and apply compensating controls as necessary.

Defensive priority

Medium

Recommended defensive actions

  • Apply patches to affected Discourse instances
  • Verify tagging configurations and staff-only tag groups
  • Monitor for unauthorized access to hidden tags
  • Review compensating controls for exposed systems
  • Check relevant monitoring, detection, and logs for exposed assets
  • Track exceptions, retest remediated assets
  • Confirm whether affected product deployments exist in managed environments

Evidence notes

The CVE record was published on 2026-04-03T22:16:25.573Z and was last modified on 2026-07-24T22:10:00.140Z. The NVD entry is currently Analyzed. The vulnerability affects Discourse instances with tagging enabled and staff-only tag groups configured. Evidence is limited to public CVE and NVD information.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-27481 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-27481

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

  • CVE-2026-27481 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-27481

    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.