CVE-2023-43658

Name: CVE-2023-43658
Creator: NVD / NIST
Published: 2023-10-16T22:15:12.143+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.50%

Last modified Jun 17, 2026

CVE-2023-43658 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. 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. EPSS estimates a 0.50% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

0.50%

39.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Discourse	Discourse Calendar	<= 2023-10-16

References

https://developer.mozilla.org/en-US/docs/Web/HTTP/CSPThird Party Advisory
https://github.com/discourse/discourse-calendar/commit/9788310906febb36822d6823d14f1059c39644dePatch
https://github.com/discourse/discourse-calendar/security/advisories/GHSA-3fwj-f6ww-7hr6Vendor Advisory
https://developer.mozilla.org/en-US/docs/Web/HTTP/CSPThird Party Advisory
https://github.com/discourse/discourse-calendar/commit/9788310906febb36822d6823d14f1059c39644dePatch
https://github.com/discourse/discourse-calendar/security/advisories/GHSA-3fwj-f6ww-7hr6Vendor Advisory

Timeline

Published: Oct 16, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-43658?

How severe is CVE-2023-43658?

CVE-2023-43658 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.50% probability of exploitation in the next 30 days.

How do I fix CVE-2023-43658?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-43658?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST