Discourse up to 2026.1.3/2026.3.0/2026.4.0 Configuration path traversal

Summaryinfo

A vulnerability, which was classified as critical, was found in Discourse up to 2026.1.3/2026.3.0/2026.4.0. This issue affects some unknown processing of the component Configuration Handler. Executing a manipulation can lead to path traversal. This vulnerability is tracked as CVE-2026-45775. The attack can be launched remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in Discourse up to 2026.1.3/2026.3.0/2026.4.0. This vulnerability affects some unknown functionality of the component Configuration Handler. The manipulation with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect confidentiality. CVE summarizes:

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, a path traversal vulnerability in Discourse backup handling could allow an authenticated administrator on one site in a multisite deployment to access backup files belonging to another site when backups are stored locally. In affected configurations, an admin on Site A could potentially retrieve sensitive backup data from Site B (same host, multisite) by crafting a backup download request with a traversal payload. This issue has been patched in versions 2026.1.4, 2026.3.1, 2026.4.1, and 2026.5.0-latest.1.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-45775 since 05/13/2026. The exploitation appears to be easy. The attack can be initiated remotely. Additional levels of successful authentication are required for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1006.

Upgrading to version 2026.1.4, 2026.3.1 or 2026.4.1 eliminates this vulnerability.

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Productinfo

Type

• Chat Software

Name

• Discourse

Version

• 2026.0
• 2026.1
• 2026.1.0
• 2026.1.1
• 2026.1.2
• 2026.1.3
• 2026.2
• 2026.3
• 2026.3.0
• 2026.4.0

License

• open-source

Website

• Product: https://github.com/discourse/discourse/

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