discourse: Externally Controlled Reference to a Resource in Another Sphere
CVE-2024-47773 is a high-severity externally controlled reference to a resource in another sphere vulnerability in discourse, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 3.3.2 as the first without the flaw, so updating discourse to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.8% chance of exploitation within 30 days, higher than 79% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update discourse to 3.3.2 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Discourse | discourse | stable: < 3.3.2; tests-passed: < 3.4.0.beta2; before 3.3.2 | 3.3.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L. Scored by CNA (github.com).
Official description
Discourse is an open source platform for community discussion. An attacker can make several XHR requests until the cache is poisoned with a response without any preloaded data. This issue only affects anonymous visitors of the site. This problem has been patched in the latest version of Discourse. Users are advised to upgrade. Users unable to upgrade should disable anonymous cache by setting the `DISCOURSE_DISABLE_ANON_CACHE` environment variable to a non-empty value.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Externally Controlled Reference to a Resource in Another Sphere
The product uses an externally controlled name or reference that resolves to a resource that is outside of the intended control sphere.
More Externally Controlled Reference to a Resource in Another Sphere vulnerabilities (CWE-610)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/discourse/discourse/security/advisories/GHSA-58vv-9j8h-hw2vThird Party Advisory
Other vulnerabilities in discourse
- 7.7 High severity
- 7.5 High severity
- 7.5 High severity
- 7.2 High severity
- 8.7 High severity
- 9.3 Critical severity
Recent Externally Controlled Reference to a Resource in Another Sphere vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 7.5 High severity
- 8.6 High severity
- 7.8 High severity
- 8.1 High severity
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