What’s Vulnerable › Vulnerabilities

CVE-2023-43657: Improper escaping of encrypted topic titles can lead to Cross-site Scripting under non-default site configuration

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-09-28 · updated 2026-06-17
• Weakness: CWE-79

Description

discourse-encrypt is a plugin that provides a secure communication channel through Discourse. Improper escaping of encrypted topic titles could lead to a cross site scripting (XSS) issue when a site has content security policy (CSP) headers disabled. Having CSP disabled is a non-default configuration, and having it disabled with discourse-encrypt installed will result in a warning in the Discourse admin dashboard. This has been fixed in commit `9c75810af9` which is included in the latest version of the discourse-encrypt plugin. Users are advised to upgrade. Users unable to upgrade should ensure that CSP headers are enabled and properly configured.

Affected products

• discourse-encrypt: before 2023-09-28 — fixed in 2023-09-28

How to fix

Upgrade to a fixed version: discourse-encrypt 2023-09-28. Check the vendor advisory for mitigations.

References

• https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP
• https://github.com/discourse/discourse-encrypt/commit/9c75810af9a474d7edaec67dea66f852c0ba1f4e
• https://github.com/discourse/discourse-encrypt/security/advisories/GHSA-5fh6-wp7p-xx7v
• https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP
• https://github.com/discourse/discourse-encrypt/commit/9c75810af9a474d7edaec67dea66f852c0ba1f4e
• https://github.com/discourse/discourse-encrypt/security/advisories/GHSA-5fh6-wp7p-xx7v

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