CVE-2026-45775: Discourse: Cross-site backup access via path traversal in multisite local backups
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Discourseto a version that resolves this vulnerability.Fixed in 2026.1.4 - Upgrade
Upgrade
Discourseto a version that resolves this vulnerability.Fixed in 2026.3.1 - Upgrade
Upgrade
Discourseto a version that resolves this vulnerability.Fixed in 2026.4.1 - Upgrade
Upgrade
Discourseto a version that resolves this vulnerability.Fixed in 2026.5.0-latest.1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-45775?
CVE-2026-45775 has a severity rating of medium with a score of 6.8.
How do I fix CVE-2026-45775?
To mitigate CVE-2026-45775, upgrade Discourse to version 2026.1.4, 2026.3.1, or 2026.4.1 or later.
What type of vulnerability is CVE-2026-45775?
CVE-2026-45775 is a path traversal vulnerability that affects the backup handling in Discourse.
What impact does CVE-2026-45775 have?
CVE-2026-45775 can allow an authenticated administrator to access unauthorized backup files across different sites in a multisite setup.
Which versions of Discourse are affected by CVE-2026-45775?
CVE-2026-45775 affects Discourse versions 2026.1.0 to before 2026.1.4, 2026.3.0 to before 2026.3.1, and 2026.4.0 to before 2026.4.1.