What’s Vulnerable › Vulnerabilities

CVE-2021-37703: Information exposure in Discourse

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-08-13 · updated 2026-06-17
• Weakness: CWE-200

Description

Discourse is an open-source platform for community discussion. In Discourse before versions 2.7.8 and 2.8.0.beta5, a user's read state for a topic such as the last read post number and the notification level is exposed.

Affected products

• discourse: before 2.7.8; 2.8.0-beta1, 2.8.0-beta2, 2.8.0-beta3, 2.8.0-beta4 — fixed in 2.7.8

How to fix

Upgrade to a fixed version: discourse 2.7.8. Check the vendor advisory for mitigations.

References

• https://github.com/discourse/discourse/commit/aed65ec16d38886d7be7209d8c02df4ffd4937a4
• https://github.com/discourse/discourse/security/advisories/GHSA-gq2h-qhg2-phf9
• https://github.com/discourse/discourse/commit/aed65ec16d38886d7be7209d8c02df4ffd4937a4
• https://github.com/discourse/discourse/security/advisories/GHSA-gq2h-qhg2-phf9

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