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TI-2023-23384 Aliases CVE-2023-43659

Cross-site Scripting via email preview when CSP disabled in Discourse

Priority LOW 37CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

Discourse is an open source platform for community discussion. Improper escaping of user input allowed for Cross-site Scripting attacks via the digest email preview UI. This issue only affects sites with CSP disabled. This issue has been patched in the 3.1.1 stable release as well as the 3.2.0.beta1 release. Users are advised to upgrade. Users unable to upgrade should ensure CSP is enabled on the forum.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00482 41st percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

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

Affected products

VendorProductAffected versionsFixed inStatusSource
discoursediscoursestable <= 3.1.1; beta <= 3.2.0.beta1—No fix listedCNA
  • discourse Vendordiscourse Affected stable <= 3.1.1; beta <= 3.2.0.beta1 Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:discourse:discourse:*:*:*:*:stable:*:*:*up to 3.1.1Vulnerablediscourse
cpe:2.3:a:discourse:discourse:3.2.0:beta1:*:*:beta:*:*:*3.2.0 beta1Vulnerablediscourse
  • cpe:2.3:a:discourse:discourse:*:*:*:*:stable:*:*:* Versions up to 3.1.1 Vulnerable ·discourse
  • cpe:2.3:a:discourse:discourse:3.2.0:beta1:*:*:beta:*:*:* Versions 3.2.0 beta1 Vulnerable ·discourse

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-43659

References

Advisory 2

  • 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