How severe is CVE-2026-27639?

CVE-2026-27639 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-27639 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-27639?

CVE-2026-27639 affects Sourcentis Mercator. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27639?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-27639 have an EU (EUVD) identifier?

Yes. CVE-2026-27639 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8613.

When was CVE-2026-27639 published?

CVE-2026-27639 was published on 2026-02-25 and last updated on 2026-06-17.

CVE-2026-27639

CVE-2026-27639 is a medium-severity vulnerability in Sourcentis Mercator with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v4: 8.5
EPSS exploit prediction: 0% (20th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-8613
Weakness: CWE-79
Affected product: Sourcentis Mercator
Published: 2026-02-25
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-27639?: 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.
How severe is CVE-2026-27639?: CVE-2026-27639 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-27639 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-27639?: CVE-2026-27639 affects Sourcentis Mercator. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27639?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-27639 have an EU (EUVD) identifier?: Yes. CVE-2026-27639 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8613.
When was CVE-2026-27639 published?: CVE-2026-27639 was published on 2026-02-25 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:sourcentis:mercator:*:*:*:*:*:*:*:*

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