Cyber Resilience

CVE-2025-48877

High

Published: 09 June 2025

Published
09 June 2025
Modified
25 September 2025
KEV Added
—
Patch
—
CVSS Score v4 8.1 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
EPSS Score 0.0069 72.3th percentile
Risk Priority 17 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-48877 is a high-severity Insecure Automated Optimizations (CWE-1038) vulnerability in Discourse Discourse. Its CVSS base score is 8.1 (High).

Operationally, ranked in the top 27.7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

more

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`.

CWE(s)
CWE-1038

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

discourse
discourse
3.5.0 · ≤ 3.4.4 · ≤ 3.5.0

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References