CVE-2021-43794 - CVE House
Back to Database
Status published Medium CVE-2021-43794

Anonymous user cache poisoning via development-mode header in Discourse

Vulnerability Description

Discourse is an open source discussion platform. In affected versions an attacker can poison the cache for anonymous (i.e. not logged in) users, such that the users are shown a JSON blob instead of the HTML page. This can lead to a partial denial-of-service. This issue is patched in the latest stable, beta and tests-passed versions of Discourse.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

THREAT MONITOR

Am I Vulnerable?

Launch our assessment wizard to check if your infrastructure is exposed to • CVE-2021-43794

Credits & Attribution

No credits recorded in the NVD database.

References

More from discourse

View All →
CVE-2025-69289
Discourse has insecure default configuration that allows non-admin moderators to takeover any non-staff account via email change
Medium 5.1
CVE-2025-69218
Discourse moderators can access admin-only reports exposing private upload URLs
High 7.1
CVE-2025-68934
Discourse Has Denial of Service (DoS) Vulnerability in Drafts Creation Endpoint
Medium 6.5
CVE-2025-68933
Discourse non-admin moderators can exfiltrate private content via post ownership transfer
Medium 6.9
CVE-2025-68666
Discourse users archives leaked to users with moderation privileges
Medium 5.9

Affected Vendor

Affected Software

discourse
Vulnerable Versions:
stable < 2.7.11, beta < 2.8.0.beta9, tests-passed < 2.8.0.beta9

Timeline

Official Publish: December 1st, 2021
Last Modified: August 4th, 2024
Added to House: July 21st, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Weaknesses (CWE)

CWE-610

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.