CVE-2026-45775
Received Received - Intake
Path Traversal in Discourse Multisite Backup Handling

Publication date: 2026-06-12

Last updated on: 2026-06-12

Assigner: GitHub, Inc.

Description
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.
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Meta Information
Published
2026-06-12
Last Modified
2026-06-12
Generated
2026-06-13
AI Q&A
2026-06-13
EPSS Evaluated
N/A
NVD
CVE-2026-45775
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
discourse discourse From 2026.1.0 (inc) to 2026.1.4 (exc)
discourse discourse From 2026.3.0 (inc) to 2026.3.1 (exc)
discourse discourse From 2026.4.0 (inc) to 2026.4.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
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.
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Executive Summary

This vulnerability is a path traversal issue in the Discourse open-source discussion platform's backup handling system. It affects certain versions of Discourse in multisite deployments where backups are stored locally. An authenticated administrator on one site within the multisite setup can exploit this vulnerability to access backup files belonging to another site on the same host by crafting a specially designed backup download request containing a traversal payload.

Impact Analysis

The impact of this vulnerability is that an authenticated administrator on one site in a multisite Discourse deployment could retrieve sensitive backup data from another site on the same host. This could lead to unauthorized access to potentially sensitive or confidential information contained in those backups, compromising data confidentiality.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade your Discourse installation to one of the patched versions: 2026.1.4, 2026.3.1, 2026.4.1, or 2026.5.0-latest.1.

This will prevent authenticated administrators on one site in a multisite deployment from accessing backup files belonging to another site via path traversal attacks.

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