How severe is CVE-2026-42030?

CVE-2026-42030 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-42030 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42030?

CVE-2026-42030 affects Osgeo Mapserver. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42030?

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

Does CVE-2026-42030 have an EU (EUVD) identifier?

Yes. CVE-2026-42030 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28807.

When was CVE-2026-42030 published?

CVE-2026-42030 was published on 2026-05-08 and last updated on 2026-06-17.

CVE-2026-42030

CVE-2026-42030 is a medium-severity vulnerability in Osgeo Mapserver with a CVSS 3.x base score of 6.1. 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-80.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-28807
Weakness: CWE-80
Affected product: Osgeo Mapserver
Published: 2026-05-08
Last modified: 2026-06-17

Description

MapServer is a system for developing web-based GIS applications. From version 6.0 to before version 8.6.2, a reflected XSS vulnerability in MapServer's WMS server allows an unauthenticated attacker to inject arbitrary HTML/JavaScript into the browser of any user who opens a crafted WMS URL. The vulnerability is triggered via FORMAT=application/openlayers combined with an unsanitized SRS parameter in WMS 1.3.0 requests. This issue has been patched in version 8.6.2.

Frequently asked questions

What is CVE-2026-42030?: MapServer is a system for developing web-based GIS applications. From version 6.0 to before version 8.6.2, a reflected XSS vulnerability in MapServer's WMS server allows an unauthenticated attacker to inject arbitrary HTML/JavaScript into the browser of any user who opens a crafted WMS URL. The vulnerability is triggered via FORMAT=application/openlayers combined with an unsanitized SRS parameter in WMS 1.3.0 requests. This issue has been patched in version 8.6.2.
How severe is CVE-2026-42030?: CVE-2026-42030 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-42030 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42030?: CVE-2026-42030 affects Osgeo Mapserver. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42030?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-42030 have an EU (EUVD) identifier?: Yes. CVE-2026-42030 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28807.
When was CVE-2026-42030 published?: CVE-2026-42030 was published on 2026-05-08 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:osgeo:mapserver:*:*:*:*:*:*:*:*

More vulnerabilities in Osgeo Mapserver

CVE-2010-2540 — Critical (CVSS 10.0): mapserv.c in mapserv in MapServer before 4.10.6 and 5.x before 5.6.4 does not properly restrict the use of CGI…
CVE-2009-2281 — Critical (CVSS 10.0): Multiple heap-based buffer underflows in the readPostBody function in cgiutil.c in mapserv in MapServer 4.x through…
CVE-2009-1177 — Critical (CVSS 10.0): Multiple stack-based buffer overflows in maptemplate.c in mapserv in MapServer 4.x before 4.10.4 and 5.x before 5.2.2…
CVE-2009-1176 — Critical (CVSS 10.0): mapserv.c in mapserv in MapServer 4.x before 4.10.4 and 5.x before 5.2.2 does not ensure that the string holding the id…
CVE-2009-0841 — Critical (CVSS 10.0): Directory traversal vulnerability in mapserv.c in mapserv in MapServer 4.x before 4.10.4 and 5.x before 5.2.2, when…
CVE-2009-0840 — Critical (CVSS 10.0): Heap-based buffer underflow in the readPostBody function in cgiutil.c in mapserv in MapServer 4.x before 4.10.4 and 5.x…

All CVEs affecting Osgeo Mapserver →

Other CWE-80 vulnerabilities

CVE-2024-39363 — Critical (CVSS 9.6): A cross-site scripting (xss) vulnerability exists in the login.cgi set_lang_CountryCode() functionality of Wavlink…
CVE-2023-39216 — Critical (CVSS 9.6): Improper input validation in Zoom Desktop Client for Windows before 5.14.7 may allow an unauthenticated user to enable…
CVE-2025-53883 — Critical (CVSS 9.3): A Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) vulnerability allows attackers to run…
CVE-2026-32891 — Critical (CVSS 9.0): Anchorr is a Discord bot for requesting movies and TV shows and receiving notifications when items are added to a media…
CVE-2026-57532 — High (CVSS 8.8): Malicious HTML content contained in the layout specification of a PDF ticket or badge layout was executed when the PDF…
CVE-2026-6002 — High (CVSS 8.8): Improper neutralization of Script-Related HTML tags in a web page (basic XSS) vulnerability in DivvyDrive Information…

Browse all CWE-80 vulnerabilities →