{"id":"CVE-2026-54355","title":"MapServer is a system for developing web-based GIS applications","summary":"MapServer is a system for developing web-based GIS applications. From 6.0 until 8.6.4, MapServer's OpenLayers HTML output for SERVICE=WMS&REQUEST=GetMap&FORMAT=application/openlayers reflects an attacker-controlled X-Forwarded-Host value…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N","cwe":["CWE-79"],"vendor":"MapServer","product":"MapServer","affected":["MapServer >= 6.0, < 8.6.4"],"published":"2026-09-17","updated":"2026-09-30","sourceUpdated":"2026-09-30T17:23:08.953","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-54355","references":[{"url":"https://github.com/MapServer/MapServer/commit/edc1033c7963fcffd160d85cf430f49aaf4a1374","label":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/commit/ff17ef190caaeaa9002ac3d1c7969ec5315c345e","label":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/pull/7517","label":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/pull/7518","label":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/releases/tag/rel-8-6-4","label":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/security/advisories/GHSA-xqj6-vjqr-33vv","label":"security-advisories@github.com"},{"url":"https://mapserver.org/development/changelog/changelog-8-6.html#changelog-8-6","label":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/security/advisories/GHSA-xqj6-vjqr-33vv","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"epss":0.005,"epssPercentile":0.42627,"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-24T20:45:53.514616Z"},"cvssSource":"cna","ingestedAt":"2026-09-17T21:29:16.981Z","slug":"CVE-2026-54355","body":"## Overview\n\nMapServer is a system for developing web-based GIS applications. From 6.0 until 8.6.4, MapServer's OpenLayers HTML output for SERVICE=WMS&REQUEST=GetMap&FORMAT=application/openlayers reflects an attacker-controlled X-Forwarded-Host value received as HTTP_X_FORWARDED_HOST through msBuildOnlineResource(), processLine(), and the [mapserv_onlineresource] substitution in src/maputil.c and src/maptemplate.c without escaping it for a single-quoted JavaScript string. When the deployment trusts the forwarded header and does not configure a fixed ows_onlineresource or MS_ONLINERESOURCE value, embedded single quotes can escape the generated URL string. An unauthenticated attacker can craft a URL that executes arbitrary JavaScript in the MapServer site origin when opened by a victim, enabling access to sessions or tokens, same-origin data and requests, and actions as the victim. This issue is fixed in version 8.6.4.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":210400,"id":"CVE-2026-54355","ts":1790286828188,"field":"exploit_available","old":"false","new":"true"}]}