{"id":"CVE-2026-54355","state":"PUBLISHED","title":"MapServer: Reflected XSS in OpenLayers HTML Output via `HTTP_X_FORWARDED_HOST`","description":"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 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.","publishedAt":"2026-09-17T20:24:32.522Z","updatedAt":"2026-09-24T20:45:56.071Z","severity":{"score":5.3,"label":"Medium","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["MapServer MapServer"],"affected":[{"vendor":"MapServer","product":"MapServer","versions":[{"version":">= 6.0, < 8.6.4","status":"affected"}]}],"references":["https://github.com/MapServer/MapServer/security/advisories/GHSA-xqj6-vjqr-33vv","https://github.com/MapServer/MapServer/pull/7517","https://github.com/MapServer/MapServer/pull/7518","https://github.com/MapServer/MapServer/commit/edc1033c7963fcffd160d85cf430f49aaf4a1374","https://github.com/MapServer/MapServer/commit/ff17ef190caaeaa9002ac3d1c7969ec5315c345e","https://github.com/MapServer/MapServer/releases/tag/rel-8-6-4","https://mapserver.org/development/changelog/changelog-8-6.html#changelog-8-6"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/54xxx/CVE-2026-54355.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-54355","state":"PUBLISHED","datePublished":"2026-09-17T20:24:32.522Z","dateUpdated":"2026-09-24T20:45:56.071Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-12T19:23:22.318Z"},"containers":{"cna":{"title":"MapServer: Reflected XSS in OpenLayers HTML Output via `HTTP_X_FORWARDED_HOST`","descriptions":[{"lang":"en","value":"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 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."}],"affected":[{"vendor":"MapServer","product":"MapServer","versions":[{"version":">= 6.0, < 8.6.4","status":"affected"}]}],"references":[{"url":"https://github.com/MapServer/MapServer/security/advisories/GHSA-xqj6-vjqr-33vv","name":"https://github.com/MapServer/MapServer/security/advisories/GHSA-xqj6-vjqr-33vv","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/MapServer/MapServer/pull/7517","name":"https://github.com/MapServer/MapServer/pull/7517","tags":["x_refsource_MISC"]},{"url":"https://github.com/MapServer/MapServer/pull/7518","name":"https://github.com/MapServer/MapServer/pull/7518","tags":["x_refsource_MISC"]},{"url":"https://github.com/MapServer/MapServer/commit/edc1033c7963fcffd160d85cf430f49aaf4a1374","name":"https://github.com/MapServer/MapServer/commit/edc1033c7963fcffd160d85cf430f49aaf4a1374","tags":["x_refsource_MISC"]},{"url":"https://github.com/MapServer/MapServer/commit/ff17ef190caaeaa9002ac3d1c7969ec5315c345e","name":"https://github.com/MapServer/MapServer/commit/ff17ef190caaeaa9002ac3d1c7969ec5315c345e","tags":["x_refsource_MISC"]},{"url":"https://github.com/MapServer/MapServer/releases/tag/rel-8-6-4","name":"https://github.com/MapServer/MapServer/releases/tag/rel-8-6-4","tags":["x_refsource_MISC"]},{"url":"https://mapserver.org/development/changelog/changelog-8-6.html#changelog-8-6","name":"https://mapserver.org/development/changelog/changelog-8-6.html#changelog-8-6","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"HIGH","subAvailabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-17T20:24:32.522Z"},"source":{"advisory":"GHSA-xqj6-vjqr-33vv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/MapServer/MapServer/security/advisories/GHSA-xqj6-vjqr-33vv","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-24T20:45:53.514616Z","id":"CVE-2026-54355","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-24T20:45:56.071Z"}}]}}}