CVE-2021-43794 json
Anonymous user cache poisoning via development-mode header in Discourse
published 2021-12-01 4 y ago modified 2026-09-08 2 mo ago also BIT-discourse-2021-43794 , EUVD-2021-30690 , GHSA-249g-pc77-65hp
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.1%
- EPSS 1.1% chance of exploitation in 30 days, percentile 64%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
Exploit prediction
1.05% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P |
| OSV | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| bitnami | discourse | <2.7.11 |
2.7.11 |
Affected products
- discourse discourse
Classification
- Weakness
-
- CWE-610 Externally Controlled Reference to a Resource in Another Sphere
References
-
github.com
/discourse/discourse/commit/2da0001965c6d8632d723c46ea5df9f22a1a23f1
patch, third-party-advisory, advisory
-
github.com
/discourse/discourse/security/advisories/GHSA-249g-pc77-65hp
third-party-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-43794
web
Sources
- CVE List CVE-2021-43794
- NVD CVE-2021-43794
- OSV BIT-discourse-2021-43794
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