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TI-2026-32932 Aliases CVE-2026-45085

Discourse: Chat misauthorization and information disclosure

Priority LOW 29CWE-200Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Information disclosure, Security bypass
Confidentiality · integrity · availability
Low · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-200 and CWE-862.

Summary

Discourse is an open-source discussion platform. From 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, four authorization/disclosure issues in the chat plugin (one also involving discourse-calendar): read-only category users could create chat threads, self-deleted chat messages could be restored by their author after channel access was revoked, moderators reviewing a flagged chat message were shown the channel's current last_message (often unrelated DM content), and calendar event payloads exposed the attached chat channel and its last message to viewers without chat access (including anonymous users). This affects sites with the chat plugin enabled; the calendar issue additionally requires discourse-calendar. This issue has been patched in versions 2026.1.4, 2026.3.1, 2026.4.1, and 2026.5.0-latest.1.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00213 11th percentileScored 2026-11-07
Fix Fixed discourse (discourse): 2026.1.4, 2026.3.1, 2026.4.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
discoursediscourse2026.1.0-latest to before 2026.1.4; 2026.3.0-latest to before 2026.3.1; 2026.4.0-latest to before 2026.4.12026.1.4, 2026.3.1, 2026.4.1Patch availableCNA
  • discourse Vendordiscourse Affected 2026.1.0-latest to before 2026.1.4; 2026.3.0-latest to before 2026.3.1; 2026.4.0-latest to before 2026.4.1 Fixed in 2026.1.4, 2026.3.1, 2026.4.1 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*before 2026.1.0; 2026.1.0 to before 2026.1.4; 2026.3.0 to before 2026.3.1; 2026.4.0 to before 2026.4.1Vulnerablediscourse
cpe:2.3:a:discourse:discourse:2026.5.0:*:*:*:latest:*:*:*2026.5.0Vulnerablediscourse
  • cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* Versions before 2026.1.0; 2026.1.0 to before 2026.1.4; 2026.3.0 to before 2026.3.1; 2026.4.0 to before 2026.4.1 Vulnerable ·discourse
  • cpe:2.3:a:discourse:discourse:2026.5.0:*:*:*:latest:*:*:* Versions 2026.5.0 Vulnerable ·discourse

Remediation

  • Fix · CNA discourse (discourse) Fixed in 2026.1.4, 2026.3.1, 2026.4.1

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-45085

References

Advisory 1

  • TI-2021-19656 Denial of Service in discourse CVSS 3.1MEDIUM 6.8
  • TI-2024-36150 Potential Backup file leaked via Nginx in Discourse CVSS 3.1HIGH 7.5
  • TI-2021-18002 RCE via malicious SNS subscription payload CVSS 3.1CRITICAL 10.0
  • TI-2026-24651 Discourse: Open redirect via `sso_destination_url` cookie in `enter` CVSS 4.0MEDIUM 5.1
  • TI-2026-22278 Discourse leaks private topic title and post excerpt via user action API endpoint CVSS 4.0HIGH 8.7
  • TI-2023-24152 Unauthenticated access to new private chat messages in Discourse CVSS 3.1HIGH 7.5
See all 262 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences