Is CVE-2026-27639 in the CISA KEV catalog?

No. CVE-2026-27639 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-27639?

CVE-2026-27639 has a CVSS v3 base score of 5.4 (MEDIUM).

What is the EPSS score for CVE-2026-27639?

CVE-2026-27639 has an EPSS score of 0.28% (20th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-27639?

Upgrade mercator to 2026.02.22 or later.

CVE & CISA-KEV Catalog

CVE-2026-27639

MEDIUM

5.4

CVSS v3

NVD

Description

Mercator is an open source web application designed to enable mapping of information systems. A stored Cross-Site Scripting (XSS) vulnerability exists in Mercator prior to version 2026.02.22 due to the use of unescaped Blade directives (`{!! !!}`) in display templates. An authenticated user with the User role can inject arbitrary JavaScript payloads into fields such as "contact point" when creating or editing entities. The payload is then executed in the browser of any user who views the affected page, including administrators. Version 2026.02.22 fixes the vulnerability.

CWE-79Cross-Site Scripting (XSS)

How to fix

Remediation Available

mercatorNVD

Affected:< 2026.02.22Fixed in:2026.02.22CVE-2026-27639derived 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

ScopeChanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

0.28%probability of exploitation in 30 days

20thpercentile

Low risk: more likely to be exploited than 20% of all known CVEs.

References

Patch3

Vendor Advisory1

github.com

Related Vulnerabilities

Other CWE-79 (Cross-Site Scripting (XSS)) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-11022	Medium	6.9	99%	-	Fix
CVE-2019-3929	Critical	9.8	99%	KEV	Fix
CVE-2020-9496	Medium	6.1	99%	-	-
CVE-2023-28341	Medium	6.1	99%	-	Fix
CVE-2018-12998	Medium	6.1	98%	-	-
CVE-2025-4123	High	7.6	98%	-	Fix

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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 2026-02-27.