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CVE-2025-48877

Discourse vulnerability

9.8 CRITICALEPSS 0.41%
  1. Published9 Jun 2025

Description

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`.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Discourse3.5.0 · < 3.5.0 · < 3.4.4

Remediation

Fixed in
Discourse≥ 3.5.0

References

Frequently asked

Is CVE-2025-48877 being actively exploited?

CVE-2025-48877 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.41%.

How severe is CVE-2025-48877?

CVE-2025-48877 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.41% probability of exploitation.

Which products are affected by CVE-2025-48877?

Affected products include Discourse.

How do I fix CVE-2025-48877?

Upgrade affected software to a fixed version, for example Discourse 3.5.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-48877 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.