Insufficient control of custom field value sizes
Priority LOW 21CWE-400Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-400.
Summary
Discourse is a platform for community discussion. For fields that are client editable, limits on sizes are not imposed. This allows a malicious actor to cause a Discourse instance to use excessive disk space and also often excessive bandwidth. The issue is patched 3.1.4 and 3.2.0.beta4.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00566 47th percentileScored 2026-11-07
Fix Fixed discourse (discourse): 3.1.4, 3.2.0.beta4
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| discourse | discourse | before 3.1.4; 3.2.0beta1 to before 3.2.0.beta4 | 3.1.4, 3.2.0.beta4 | Patch available | CNA |
- discourse Vendordiscourse Affected before 3.1.4; 3.2.0beta1 to before 3.2.0.beta4 Fixed in 3.1.4, 3.2.0.beta4 Patch available CNA
CPE configurations NVD · 4
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:discourse:discourse:*:*:*:*:stable:*:*:* | before 3.1.4 | Vulnerable | discourse |
| cpe:2.3:a:discourse:discourse:3.2.0:beta1:*:*:beta:*:*:* | 3.2.0 beta1 | Vulnerable | discourse |
| cpe:2.3:a:discourse:discourse:3.2.0:beta2:*:*:beta:*:*:* | 3.2.0 beta2 | Vulnerable | discourse |
| cpe:2.3:a:discourse:discourse:3.2.0:beta3:*:*:beta:*:*:* | 3.2.0 beta3 | Vulnerable | discourse |
- cpe:2.3:a:discourse:discourse:*:*:*:*:stable:*:*:* Versions before 3.1.4 Vulnerable ·discourse
- cpe:2.3:a:discourse:discourse:3.2.0:beta1:*:*:beta:*:*:* Versions 3.2.0 beta1 Vulnerable ·discourse
- cpe:2.3:a:discourse:discourse:3.2.0:beta2:*:*:beta:*:*:* Versions 3.2.0 beta2 Vulnerable ·discourse
- cpe:2.3:a:discourse:discourse:3.2.0:beta3:*:*:beta:*:*:* Versions 3.2.0 beta3 Vulnerable ·discourse
Remediation
- Fix · CNA discourse (discourse) Fixed in 3.1.4, 3.2.0.beta4
Timeline
- 2026-10-02 Threatist record created from CVE-2024-21655
References
More Discourse vulnerabilities
- TI-2021-19656 Denial of Service in discourse CVSS 3.1MEDIUM 6.8
- TI-2024-36150 Potential Backup file leaked via Nginx in Discourse CVSS 3.1HIGH 7.5
- TI-2021-18002 RCE via malicious SNS subscription payload CVSS 3.1CRITICAL 10.0
- TI-2026-24651 Discourse: Open redirect via `sso_destination_url` cookie in `enter` CVSS 4.0MEDIUM 5.1
- TI-2026-22278 Discourse leaks private topic title and post excerpt via user action API endpoint CVSS 4.0HIGH 8.7
- TI-2023-24152 Unauthenticated access to new private chat messages in Discourse CVSS 3.1HIGH 7.5
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences