CVE-2026-102396

Executive Summary

CVE-2026-102396 is an unauthenticated Cross-Site Scripting (XSS) vulnerability affecting the WordPress plugin "Ultimate Maps by Supsystic" in versions up to and including 1.5.5. Because exploitation requires no authentication and only user interaction (a victim visiting or interacting with a crafted request), the flaw exposes every site running the affected plugin version to script injection through the browser of an authenticated or anonymous visitor. Successful exploitation can lead to session theft, credential harvesting, malicious redirects, drive-by downloads, or full site takeover when a privileged user (such as an administrator) is targeted.

Technical Analysis

The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation, commonly "Cross-Site Scripting"). The NVD description identifies it as an unauthenticated XSS issue in Ultimate Maps by Supsystic versions <= 1.5.5.

The CVSS v3.1 vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L (base score 7.1, HIGH) tells us the following about the mechanism:

• AV:N (Network) — the attack is delivered remotely over the network; no local access to the server is needed.
• AC:L (Low) — no specialized conditions or race windows are required; the attack is straightforward once a target is identified.
• PR:N (None) — the attacker does not need any account or privileges on the target site, which is the defining "unauthenticated" characteristic.
• UI:R (Required) — a victim user must perform some interaction, the classic requirement for reflected/DOM-based XSS where the payload must be rendered in a victim's browser.
• S:C (Changed) — the impact extends beyond the vulnerable component (the plugin's own security scope) to the surrounding page, browser session, or WordPress context, consistent with injected script executing with the origin's privileges.
• C:L / I:L / A:L (Low) — limited confidentiality, integrity, and availability impact, typical for XSS where script execution grants access to cookies, DOM, and same-origin resources but not direct server-side takeover.

Because no CNA title, affected-version list beyond <= 1.5.5, function names, endpoints, or parameter names are provided in the source data, the specific injection point cannot be stated with confidence. Based on the vulnerability class, the flaw is most plausibly an input-handling failure in which a request parameter, map configuration field, or shortcode attribute is echoed into the generated HTML/JavaScript without proper output encoding or sanitization. When a victim loads a page that reflects or renders that input, the attacker's script executes in the browser within the site's origin.

An important operational nuance: WordPress plugins are commonly bundled into themes or deployed across large numbers of sites through marketplaces and managed hosts, so "unpatched source" does not mean "no installed base" — it means there is no upstream fix to apply, forcing compensating controls.

Exploitation Scenarios

No public PoC, exploit code, or Nuclei template is available for this CVE. The chain below is described at the vulnerability-class level in accordance with the data provided; no specific function names, endpoints, file paths, or parameters are asserted because none appear in the source description.

1. Reconnaissance / target identification. An attacker enumerates WordPress sites and fingerprints those running the Ultimate Maps by Supsystic plugin at version <= 1.5.5. Plugin detection can be performed passively through page source references (asset paths, plugin identifiers) or via search engines and internet-scanning services. Sites with the affected version and no WAF/CDN filtering are prioritized.

2. Triggering the flaw. Because the vulnerability is unauthenticated, the attacker does not need to log in. The attacker crafts a request that delivers a malicious script payload to an input that the plugin fails to neutralize before it is reflected or rendered in a web page (CWE-79). The exact sink is not disclosed in the available data; generically, the payload is embedded in a request parameter, map setting, or markup field that the plugin outputs without encoding.

3. Payload / execution method (vulnerability-class level). The attacker delivers a link or reference to the crafted request to a victim (UI:R). When the victim loads the affected page, the injected markup causes the browser to execute attacker-controlled JavaScript in the context of the target site's origin. Script execution at the vulnerability-class level can read the victim's DOM, cookies not marked HttpOnly, and localStorage; issue same-origin requests; and modify page content. No specific URL, parameter, or payload is asserted here because the source data does not provide them.

4. Post-exploitation impact. Given the S:C scope change and Low C/I/A subscores, realistic outcomes include: theft of session tokens or CSRF tokens from an authenticated victim's browser; performing privileged actions on behalf of an administrator (for example, plugin/theme installation or user creation, if that user is targeted); injecting persistent redirects, malvertising, or phishing pages; and using the compromised site as a pivot or watering-hole. Impact escalates substantially when the targeted victim holds administrative privileges, moving from client-side compromise to full site takeover in practice.

Impact Assessment

• Business impact: Any organization hosting or providing WordPress sites that include Ultimate Maps by Supsystic <= 1.5.5 — including agencies, managed hosting providers, and enterprises with marketing or microsites — is affected. XSS can lead to reputational damage, SEO poisoning, defacement, and downstream compromise of visitors.
• Affected systems: WordPress installations with the affected plugin version. The plugin is deployed as a third-party component, so the "product" is commonly inherited indirectly by site owners.
• Blast radius: The vulnerable component is only the plugin, but the S:C scope change means the attacker's impact is not confined to that component — it extends to the enclosing page and the victim's browser session. Confidentiality, Integrity, and Availability are each rated Low per CVSS, but aggregate business impact can be High when administrative sessions are stolen.
• Exploitability: AC:L and PR:N make the flaw highly attractive for opportunistic, automated mass-scanning attacks once an exploit is public. UI:R is the only meaningful friction, which is trivially overcome with social engineering or a crafted link.
• CVSS summary: Base 7.1 (HIGH) — AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L.
• EPSS: Not yet scored by FIRST.org; no exploit-in-the-wild evidence has been observed as of this report.

Detection Guidance

Sigma Rule

title: Suspicious Unauthenticated XSS Probe Against Ultimate Maps by Supsystic (CVE-2026-102396)
id: 3f9a7c12-6d4e-4b8a-9f21-0d9c1e7a5b44
status: experimental
description: Detects requests to a WordPress site containing script-injection indicators commonly used to test for reflected/DOM XSS in Ultimate Maps by Supsystic <= 1.5.5.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-102396
author: valtersit.com threat intel
date: 2026/01/01
logsource:
  category: webserver
  product: apache
detection:
  selection_uri:
    cs-uri-query|contains:
      - 'ultimate-maps'
      - 'supsystic'
  selection_payload:
    cs-uri-query|contains:
      - '<script'
      - '%3Cscript'
      - 'onerror='
      - 'onload='
      - 'javascript:'
      - 'document.cookie'
  condition: selection_uri and selection_payload
falsepositives:
  - Legitimate administrative or security scanning activity
level: high

YARA Rule

rule CVE_2026_102396_XSS_Ultimate_Maps_Supsystic
{
    meta:
        description = "Detects reflected XSS payload markers targeting Ultimate Maps by Supsystic <= 1.5.5"
        author = "valtersit.com threat intel"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-102396"
        date = "2026-01-01"
        cve = "CVE-2026-102396"
    strings:
        $plugin = "ultimate-maps" ascii wide nocase
        $supsystic = "supsystic" ascii wide nocase
        $x1 = "<script" ascii nocase
        $x2 = "javascript:" ascii nocase
        $x3 = "onerror=" ascii nocase
        $x4 = "document.cookie" ascii nocase
    condition:
        ( $plugin or $supsystic ) and any of ( $x* )
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-102396 Potential XSS against Ultimate Maps by Supsystic"; flow:established,to_server; http.uri; content:"ultimate-maps"; fast_pattern; http.uri; pcre:"/(%3C|<)script|onerror=|onload=|javascript:/i"; classtype:web-application-attack; reference:cve,2026-102396; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-102396; sid:2026102396; rev:1;)

Elastic Detection

sequence by source.ip with maxspan=1m
  [http where http.request.method == "GET" and url.path contains "ultimate-maps"]
  [http where http.request.method == "GET" and (url.query contains "<script" or url.query contains "%3Cscript" or url.query contains "onerror" or url.query contains "javascript:")]

Splunk SPL Query

index=web (sourcetype=access_combined OR sourcetype=nginx:access)
| eval uq=urldecode(uri_query)
| where match(uri,"(?i)ultimate-maps|supsystic") AND match(uq,"(?i)<script|%3Cscript|onerror=|onload=|javascript:|document\.cookie")
| stats count min(_time) as first_seen max(_time) as last_seen by src_ip, uri_path, uq
| sort - count

Wazuh OSSEC Rule

<group name="web,appsecurity,cve-2026-102396,">
  <rule id="102396" level="10">
    <decoded_as>apache2</decoded_as>
    <regex_url>ultimate-maps|supsystic</regex_url>
    <match>(?i)%3Cscript|&lt;script|onerror=|onload=|javascript:</match>
    <description>CVE-2026-102396: Possible XSS attempt against Ultimate Maps by Supsystic.</description>
    <mitre>
      <id>T1059.007</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source).

1. Immediate mitigations

   • Deploy a Web Application Firewall (WAF) or reverse-proxy filtering rule tuned to block XSS payload markers in requests touching the plugin's routes (script tags, event handlers, javascript: URIs, encoded variants). The Suricata rule above can serve as a starting point.
   • Enforce a strict Content Security Policy (CSP) to reduce the impact of reflected/DOM XSS, since no patched plugin version is available. Back it with X-Content-Type-Options: nosniff and SameSite cookies.
   • Disable or remove the Ultimate Maps by Supsystic plugin if its map functionality is not required; if it is required, isolate affected sites behind a filtering CDN and monitor for anomalous outbound requests from administrator sessions.
   • Harden privileged accounts: use unique, strong credentials, enforce MFA, and keep administrator session lifetimes short to limit the value of stolen cookies.

2. Patch / upgrade steps

   • There is no vendor fix in tracked sources for versions <= 1.5.5. Do not assume an upgrade exists — verify the vendor's site directly before relying on any "latest version." Until an official release is published and validated, treat affected versions as permanently vulnerable and rely on compensating controls (WAF, CSP, monitoring).
   • When a fixed release does become available, stage it in a non-production environment, validate map functionality, then roll out promptly and confirm the version in the plugin inventory.

3. Long-term hardening

   • Maintain a software bill of materials for WordPress plugins/themes and subscribe to vendor or vulnerability feeds so future plugin CVEs are caught early.
   • Adopt the principle of least privilege for WordPress users and avoid daily-driver administrative browsing on public-facing sites.
   • Apply centralized WAF + CSP + logging across all WordPress properties, and regularly test XSS handling with an internal security review program.

References

• NVD — CVE-2026-102396: https://nvd.nist.gov/vuln/detail/CVE-2026-102396
• MITRE CWE-79 (Improper Neutralization of Input During Web Page Generation — Cross-Site Scripting): https://cwe.mitre.org/data/definitions/79.html
• MITRE ATT&CK T1059.007 (Command and Scripting Interpreter: JavaScript): https://attack.mitre.org/techniques/T1059/007/
• FIRST.org EPSS (currently un-scored for this CVE): https://www.first.org/epss/
• CISA Known Exploited Vulnerabilities Catalog (verify current status; not listed at time of writing): https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• Ultimate Maps by Supsystic plugin product page / vendor advisories — consult the official Supsystic site and the WordPress.org plugin repository for any forthcoming patch or advisory.

No threat actor campaigns or exploit-in-the-wild evidence were identified for this CVE at the time of publication; PoC, exploit code, and Nuclei templates are all reported as unavailable.