Is CVE-2025-66488 in the CISA KEV catalog?

No. CVE-2025-66488 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2025-66488?

CVE-2025-66488 has a CVSS v3 base score of 4.6 (MEDIUM).

What is the EPSS score for CVE-2025-66488?

CVE-2025-66488 has an EPSS score of 0.17% (7th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2025-66488?

Upgrade discourse to 2025.11.2 or later.

CVE & CISA-KEV Catalog

CVE-2025-66488

MEDIUM

4.6

CVSS v3

NVD

Description

Discourse is an open source discussion platform. A vulnerability present in versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 affects anyone who uses S3 for uploads. While scripts may be executed, they will only be run in the context of the S3/CDN domain, with no site credentials. Versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 fix the issue. As a workaround, disallow html or xml files for uploads in authorized_extensions. For existing html xml uploads, site owners can consider deleting them.

CWE-116

How to fix

Remediation Available

discourseNVD

Affected:>= 2025.11.0, < 2025.11.2Fixed in:2025.11.2CVE-2025-66488derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityLow

AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L

Exploit Intelligence

0.17%probability of exploitation in 30 days

7thpercentile

Low risk: more likely to be exploited than 7% of all known CVEs.

References

Third-Party Advisory1

github.com

Related Vulnerabilities

Other CWE-116 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-38475	Critical	9.1	100%	KEV	Fix
CVE-2022-36446	Critical	9.8	96%	-	Fix
CVE-2021-31806	Medium	6.5	96%	-	Fix
CVE-2022-30781	High	7.5	88%	-	Fix
CVE-2022-36099	Critical	9.9	76%	-	Fix
CVE-2022-36100	Critical	9.9	74%	-	Fix

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Markdown

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HTML

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-01-30.