{"id":"DEBIAN-CVE-2026-54355","details":"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.","modified":"2026-09-25T08:47:22.472909945Z","published":"2026-09-17T21:17:15.410Z","upstream":["CVE-2026-54355"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-54355"}],"affected":[{"package":{"name":"mapserver","ecosystem":"Debian:12","purl":"pkg:deb/debian/mapserver?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["8.0.0-3","8.0.0-3+deb12u1","8.0.1-1","8.0.1-1~exp1","8.0.1-2","8.0.1-2.1~exp1","8.0.1-2~bpo12+1","8.0.1-3","8.0.1-3~exp1","8.0.1-4","8.0.1-5","8.0.2-1","8.0.2-1~bpo12+1","8.2.0-1","8.2.0-1~bpo12+1","8.2.0~beta1-1~exp1","8.2.0~beta2-1~exp1","8.2.0~beta3-1~exp1","8.2.0~rc1-1~exp1","8.2.0~rc2-1~exp1","8.2.0~rc3-1~exp1","8.2.1-1","8.2.1-1~bpo12+1","8.2.2-1","8.2.2-1~bpo12+1","8.4.0-1","8.4.0-1~bpo12+1","8.4.0-2","8.4.0-3","8.4.0-4","8.4.0~beta1-1~exp1","8.4.0~beta2-1~exp1","8.4.0~rc1-1~exp1","8.4.1-1","8.4.1-1~bpo13+1","8.4.1-2","8.6.0-1","8.6.0-1~bpo13+1","8.6.0~beta1-1~exp1","8.6.0~beta2-1~exp1","8.6.0~rc1-1~exp1","8.6.1-1","8.6.1-1~bpo13+1","8.6.2-1","8.6.2-1~bpo13+1","8.6.3-1","8.6.3-1~bpo13+1","8.6.4-1","8.6.4-1~bpo13+1","8.6.5-1","8.6.5-1~bpo13+1","8.6.6-1","8.6.6-1~bpo13+1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54355.json"}},{"package":{"name":"mapserver","ecosystem":"Debian:13","purl":"pkg:deb/debian/mapserver?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["8.4.0-4","8.4.0-4+deb13u1","8.4.0-4+deb13u2","8.4.1-1","8.4.1-1~bpo13+1","8.4.1-2","8.6.0-1","8.6.0-1~bpo13+1","8.6.0~beta1-1~exp1","8.6.0~beta2-1~exp1","8.6.0~rc1-1~exp1","8.6.1-1","8.6.1-1~bpo13+1","8.6.2-1","8.6.2-1~bpo13+1","8.6.3-1","8.6.3-1~bpo13+1","8.6.4-1","8.6.4-1~bpo13+1","8.6.5-1","8.6.5-1~bpo13+1","8.6.6-1","8.6.6-1~bpo13+1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54355.json"}},{"package":{"name":"mapserver","ecosystem":"Debian:14","purl":"pkg:deb/debian/mapserver?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.6.4-1"}]}],"versions":["8.4.0-4","8.4.1-1","8.4.1-1~bpo13+1","8.4.1-2","8.6.0-1","8.6.0-1~bpo13+1","8.6.0~beta1-1~exp1","8.6.0~beta2-1~exp1","8.6.0~rc1-1~exp1","8.6.1-1","8.6.1-1~bpo13+1","8.6.2-1","8.6.2-1~bpo13+1","8.6.3-1","8.6.3-1~bpo13+1","8.6.4-1~bpo13+1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54355.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}