CVE-2026-54355: From 6.0 until 8.6.4, MapServer's OpenLayers HTML output for SERVICE=WMS&REQUEST=GetMap&FORMAT=application/openlayers reflects an
Affects mapserverSource GCVE Database
Not known to be exploited · CVSS 5.3 Medium · fixed in 8.6.4 : update mapserver when convenient.
Data as of 7 Nov 2026, 23:24 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 8.6.4
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 7 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSmapserverpkg:deb/ubuntu/mapserver?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSmapserverpkg:deb/ubuntu/mapserver?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSmapserverpkg:deb/ubuntu/mapserver?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSmapserverpkg:deb/ubuntu/mapserver?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Ubuntu 18.04 LTSmapserverpkg:deb/ubuntu/mapserver?arch=source&distro=bionicOther threats | Affected
| Fixed in– |
Ubuntu 16.04 LTSmapserverpkg:deb/ubuntu/mapserver?arch=source&distro=xenialOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
This vulnerability is fixed in MapServer version 8.6.4. Users should upgrade to version 8.6.4 or later to remediate this issue. If upgrading is not immediately possible, ensure that the deployment does not trust the X-Forwarded-Host header by configuring fixed values for ows_onlineresource or MS_ONLINERESOURCE to prevent injection of attacker-controlled values. No other specific mitigations are indicated.
Description
MapServer versions from 6.0 up to 8.6.4 have a vulnerability in the OpenLayers HTML output for WMS GetMap requests with application/openlayers format. The vulnerability allows an attacker to inject arbitrary JavaScript by manipulating the X-Forwarded-Host HTTP header when the deployment trusts this header and does not set fixed online resource values. This can lead to cross-site scripting (XSS) attacks, enabling session token theft and unauthorized actions in the context of the victim's browser. The issue is fixed in version 8.6.4.
References
- ubuntu.com/security/CVE-2026-54355 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-54355 (opens in a new tab)
- github.com/MapServer/MapServer/security/advisories/GHSA-xqj6-vjqr-33vv (opens in a new tab)
- github.com/MapServer/MapServer/pull/7517 (opens in a new tab)
- github.com/MapServer/MapServer/pull/7518 (opens in a new tab)
- github.com/MapServer/MapServer/commit/edc1033c7963fcffd160d85cf430f49aaf4a1374 (opens in a new tab)
- github.com/MapServer/MapServer/commit/ff17ef190caaeaa9002ac3d1c7969ec5315c345e (opens in a new tab)
- github.com/MapServer/MapServer/releases/tag/rel-8-6-4 (opens in a new tab)
- mapserver.org/development/changelog/changelog-8-6.html (opens in a new tab)