Discourse allows iframe injection though default site setting
Priority LOW 27CWE-1021Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Spoofing
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-1021.
Summary
Discourse is an open source discussion platform. Prior to 3.2.5 and 3.3.0.beta5, the vulnerability allows an attacker to inject iframes from any domain, bypassing the intended restrictions enforced by the allowed_iframes setting. This vulnerability is fixed in 3.2.5 and 3.3.0.beta5.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00345 28th percentileScored 2026-11-07
Fix Fixed discourse (discourse): 3.2.5, 3.3.0.beta5
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 3.2.5; 3.3.0.beta1 to before 3.3.0.beta5 | 3.2.5, 3.3.0.beta5 | Patch available | CNA |
- discourse Vendordiscourse Affected before 3.2.5; 3.3.0.beta1 to before 3.3.0.beta5 Fixed in 3.2.5, 3.3.0.beta5 Patch available CNA
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:discourse:discourse:*:*:*:*:stable:*:*:* | before 3.2.5 | Vulnerable | discourse |
| cpe:2.3:a:discourse:discourse:3.3.0:beta1:*:*:beta:*:*:* | 3.3.0 beta1 | Vulnerable | discourse |
| cpe:2.3:a:discourse:discourse:3.3.0:beta2:*:*:beta:*:*:* | 3.3.0 beta2 | Vulnerable | discourse |
| cpe:2.3:a:discourse:discourse:3.3.0:beta3:*:*:beta:*:*:* | 3.3.0 beta3 | Vulnerable | discourse |
| cpe:2.3:a:discourse:discourse:3.3.0:beta4:*:*:beta:*:*:* | 3.3.0 beta4 | Vulnerable | discourse |
- cpe:2.3:a:discourse:discourse:*:*:*:*:stable:*:*:* Versions before 3.2.5 Vulnerable ·discourse
- cpe:2.3:a:discourse:discourse:3.3.0:beta1:*:*:beta:*:*:* Versions 3.3.0 beta1 Vulnerable ·discourse
- cpe:2.3:a:discourse:discourse:3.3.0:beta2:*:*:beta:*:*:* Versions 3.3.0 beta2 Vulnerable ·discourse
- cpe:2.3:a:discourse:discourse:3.3.0:beta3:*:*:beta:*:*:* Versions 3.3.0 beta3 Vulnerable ·discourse
- cpe:2.3:a:discourse:discourse:3.3.0:beta4:*:*:beta:*:*:* Versions 3.3.0 beta4 Vulnerable ·discourse
Remediation
- Fix · CNA discourse (discourse) Fixed in 3.2.5, 3.3.0.beta5
Timeline
- 2026-10-02 Threatist record created from CVE-2024-39320
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