CVE-2021-43850
Denial of Service in discourse
Discourse is an open source platform for community discussion. In affected versions admins users can trigger a Denial of Service attack via the /message-bus/_diagnostics path. The impact of this vulnerability is greater on multisite Discourse instances (where multiple forums are served from a single application server) where any admin user on any of the forums are able to visit the /message-bus/_diagnostics path. The problem has been patched. Please upgrade to 2.8.0.beta10 or 2.7.12. No workarounds for this issue exist.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Denial of Service in discourse
Discourse is an open source platform for community discussion. In affected versions admins users can trigger a Denial of Service attack via the /message-bus/_diagnostics path. The impact of this vulnerability is greater on multisite Discourse instances (where multiple forums are served from a single application server) where any admin user on any of the forums are able to visit the /message-bus/_diagnostics path. The problem has been patched. Please upgrade to 2.8.0.beta10 or 2.7.12. No workarounds for this issue exist.
- Record
CVE-2021-43850- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2021-30719
Discourse is an open source platform for community discussion. In affected versions admins users can trigger a Denial of Service attack via the /message-bus/_diagnostics path. The impact of this vulnerability is greater on multisite Discourse instances (where multiple forums are served from a single application server) where any admin user on any of the forums are able to visit the /message-bus/_diagnostics path. The problem has been patched. Please upgrade to 2.8.0.beta10 or 2.7.12. No workarounds for this issue exist.
- Record
EUVD-2021-30719- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:N/A:H - Updated
- 2026-11-02
NVD
Discourse is an open source platform for community discussion. In affected versions admins users can trigger a Denial of Service attack via the /message-bus/_diagnostics path. The impact of this vulnerability is greater on multisite Discourse instances (where multiple forums are served from a single application server) where any admin user on any of the forums are able to visit the /message-bus/_diagnostics path. The problem has been patched. Please upgrade to 2.8.0.beta10 or 2.7.12. No workarounds for this issue exist.
- Record
CVE-2021-43850- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:N/A:H - CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H - CVSS 2.0
- 4.0 Medium
AV:N/AC:L/Au:S/C:N/I:N/A:P - Weakness
- CWE-20
- Updated
- 2026-11-02
OSV
Discourse is an open source platform for community discussion. In affected versions admins users can trigger a Denial of Service attack via the /message-bus/_diagnostics path. The impact of this vulnerability is greater on multisite Discourse instances (where multiple forums are served from a single application server) where any admin user on any of the forums are able to visit the /message-bus/_diagnostics path. The problem has been patched. Please upgrade to 2.8.0.beta10 or 2.7.12. No workarounds for this issue exist.
- Record
CVE-2021-43850- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H - Updated
- 2026-11-02
OSVBIT-discourse-2021-43850 No score
Denial of Service in discourse
Discourse is an open source platform for community discussion. In affected versions admins users can trigger a Denial of Service attack via the /message-bus/_diagnostics path. The impact of this vulnerability is greater on multisite Discourse instances (where multiple forums are served from a single application server) where any admin user on any of the forums are able to visit the /message-bus/_diagnostics path. The problem has been patched. Please upgrade to 2.8.0.beta10 or 2.7.12. No workarounds for this issue exist.
- Record
BIT-discourse-2021-43850- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
discourseBitnami |
before 2.7.12 | 2.7.12 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-43850 is a medium vulnerability (CVSS 6.8) in Discourse, published January 4, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.85%, the 58th percentile. Fixed in discourse 2.7.12.