{"id":"CVE-2026-54355","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-54355","generatedAt":"2026-10-28T01:50:34.894Z","title":"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(),…","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.","published":"2026-09-17T21:17:15.000Z","lastModified":"2026-09-30T17:23:09.000Z","status":"Awaiting Analysis","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"4.0","score":5.3,"severity":"MEDIUM","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-79"],"affected":[],"epss":{"score":0.005,"percentile":0.42554,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.50%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/MapServer/MapServer/commit/edc1033c7963fcffd160d85cf430f49aaf4a1374","source":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/commit/ff17ef190caaeaa9002ac3d1c7969ec5315c345e","source":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/pull/7517","source":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/pull/7518","source":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/releases/tag/rel-8-6-4","source":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/security/advisories/GHSA-xqj6-vjqr-33vv","source":"security-advisories@github.com"},{"url":"https://mapserver.org/development/changelog/changelog-8-6.html#changelog-8-6","source":"security-advisories@github.com"},{"url":"https://github.com/MapServer/MapServer/security/advisories/GHSA-xqj6-vjqr-33vv","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-54355","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}