CVE-2025-59337: Discourse: Cross-Site Data Exposure via Backup Restore Metacommand Injection in Multisite Deployments

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: 2025-10-01 · updated 2026-10-19
Weakness: CWE-77

Description

Discourse is an open-source community discussion platform. In versions 3.5.0 and below, malicious meta-commands could be embedded in a backup dump and executed during restore. In multisite setups, this allowed an admin of one site to access data or credentials from other sites. This issue is fixed in version 3.5.1.

Affected products

discourse: before 3.5.1; before 3.6.0; 3.6.0-beta1 — fixed in 3.5.1, 3.6.0

How to fix

Upgrade to a fixed version: discourse 3.5.1, 3.6.0. Check the vendor advisory for mitigations.

References

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