CVE-2026-42030Public exploitNetwork attack vector

Reflected XSS via unescaped WMS SRS parameter

Published May 8, 2026 · Updated May 8, 2026

Reflected XSS in MapServer 6.0 through 8.6.1 allows remote attackers to run JavaScript in a victim's browser through a crafted WMS URL. The WMS 1.3.0 path accepts the legacy SRS alias without validation and places it unescaped into HTML generated for FORMAT=application/openlayers. Exploitation requires a user to open the crafted URL; injected script runs in that user's browser with no reported availability impact.

CVSS severity6.1
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in MapServer 6.0 through 8.6.1 allows remote attackers to run JavaScript in a victim's browser through a crafted WMS URL. The WMS 1.3.0 path accepts the legacy SRS alias without validation and places it unescaped into HTML generated for FORMAT=application/openlayers. Exploitation requires a user to open the crafted URL; injected script runs in that user's browser with no reported availability impact.

The record

CVE
CVE-2026-42030
Published
May 8, 2026
Updated
May 8, 2026
Vendor
MapServer
Product
MapServer
Classifications
CWE-80, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 6.0, < 8.6.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

MapServer · MapServerversion=>= 6.0, < 8.6.2

Published CVSS scores

6.1GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
T1189Drive-by Compromise

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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