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TI-2023-23383 Aliases CVE-2023-43658

Improper escaping of user input in discourse-calendar

Priority LOW 38CWE-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
Fixed

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

Summary

dicourse-calendar is a plugin for the Discourse messaging platform which adds the ability to create a dynamic calendar in the first post of a topic. Improper escaping of event titles could lead to Cross-site Scripting (XSS) within the 'email preview' UI when a site has CSP disabled. Having CSP disabled is a non-default configuration, so the vast majority of sites are unaffected. This problem is resolved in the latest version of the discourse-calendar plugin. 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 0.00591 48th percentileScored 2026-11-07
Fix Fixed discourse-calendar (discourse): 97883109

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
discoursediscourse-calendarbefore 9788310997883109Patch availableCNA
  • discourse-calendar Vendordiscourse Affected before 97883109 Fixed in 97883109 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:discourse:discourse_calendar:*:*:*:*:*:discourse:*:*up to 2023-10-16Vulnerablediscourse
  • cpe:2.3:a:discourse:discourse_calendar:*:*:*:*:*:discourse:*:* Versions up to 2023-10-16 Vulnerable ·discourse

Remediation

  • Fix · CNA discourse-calendar (discourse) Fixed in 97883109

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-43658

References

Patch 1

Advisory 2

  • TI-2022-13104 Discourse Calendar Event names susceptible to Cross-site Scripting CVSS 3.1MEDIUM 6.5
  • TI-2024-14381 Insufficient control of region value length in discourse-calendar CVSS 3.1MEDIUM 4.3

Sources

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