What’s Vulnerable › Vulnerabilities
CVE-2026-45775: Discourse: Cross-site backup access via path traversal in multisite local backups
- Severity: medium (CVSS 6.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-06-12 · updated 2026-06-17
- Weakness: CWE-22
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.
Affected products
- discourse: before 2026.1.0; from 2026.1.0 before 2026.1.4; from 2026.3.0 before 2026.3.1; from 2026.4.0 before 2026.4.1; 2026.5.0 — fixed in 2026.1.0, 2026.1.4, 2026.3.1, 2026.4.1
How to fix
Upgrade to a fixed version: discourse 2026.1.0, 2026.1.4, 2026.3.1, 2026.4.1. Check the vendor advisory for mitigations.
References
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