CVE-2025-48877
Discourse vulnerable to auto-executing of third-party code in embedded CodePen iframe
Discourse is an open-source discussion platform. Prior to version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch, Codepen is present in the default allowed_iframes site setting, and it can potentially auto-run arbitrary JS in the iframe scope, which is unintended. This issue is patched in version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch. As a workaround, the Codepen prefix can be removed from a site's allowed_iframes.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Discourse vulnerable to auto-executing of third-party code in embedded CodePen iframe
Discourse is an open-source discussion platform. Prior to version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch, Codepen is present in the default allowed_iframes site setting, and it can potentially auto-run arbitrary JS in the iframe scope, which is unintended. This issue is patched in version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch. As a workaround, the Codepen prefix can be removed from a site's allowed_iframes.
- Record
CVE-2025-48877- CVSS 4.0
- 8.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U - Weakness
- CWE-1038
- Updated
- 2026-11-02
EUVDEUVD-2025-17469
Discourse is an open-source discussion platform. Prior to version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch, Codepen is present in the default allowed_iframes site setting, and it can potentially auto-run arbitrary JS in the iframe scope, which is unintended. This issue is patched in version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch. As a workaround, the Codepen prefix can be removed from a site's allowed_iframes.
- Record
EUVD-2025-17469- CVSS 4.0
- 8.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U - Updated
- 2026-11-02
NVD
Discourse is an open-source discussion platform. Prior to version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch, Codepen is present in the default allowed_iframes site setting, and it can potentially auto-run arbitrary JS in the iframe scope, which is unintended. This issue is patched in version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch. As a workaround, the Codepen prefix can be removed from a site's allowed_iframes.
- Record
CVE-2025-48877- CVSS 4.0
- 8.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-1038
- Updated
- 2026-11-02
OSV
Discourse vulnerable to auto-executing of third-party code in embedded CodePen iframe
Discourse is an open-source discussion platform. Prior to version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch, Codepen is present in the default allowed_iframes site setting, and it can potentially auto-run arbitrary JS in the iframe scope, which is unintended. This issue is patched in version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch. As a workaround, the Codepen prefix can be removed from a site's allowed_iframes.
- Record
CVE-2025-48877- CVSS 4.0
- 8.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U - Weakness
- CWE-1038
- Updated
- 2026-11-02
OSVBIT-discourse-2025-48877 No score
Discourse vulnerable to auto-executing of third-party code in embedded CodePen iframe
Discourse is an open-source discussion platform. Prior to version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch, Codepen is present in the default allowed_iframes site setting, and it can potentially auto-run arbitrary JS in the iframe scope, which is unintended. This issue is patched in version 3.4.4 of the stable branch, version 3.5.0.beta5 of the beta branch, and version 3.5.0.beta6-dev of the tests-passed branch. As a workaround, the Codepen prefix can be removed from a site's allowed_iframes.
- Record
BIT-discourse-2025-48877- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
discourseBitnami |
before 3.4.4 | 3.4.4 |
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-2025-48877 is a high vulnerability (CVSS 8.1) in Discourse, published June 9, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. Fixed in discourse 3.4.4.