CVE-2026-73377

Executive Summary

CVE-2026-73377 is an unauthenticated broken access control vulnerability in the Ultimate Maps plugin by Supsystic, affecting all versions prior to 1.5.0. The flaw maps to CWE-862 (Missing Authorization) and allows any remote, unauthenticated attacker to invoke administrative or protected operations exposed by the plugin over HTTP, resulting in a high integrity impact to affected websites. With a CVSS base score of 7.5 (High) and no requirement for authentication, user interaction, or special network access, the vulnerability is trivially exploitable against any internet-facing deployment and current threat intelligence indicates no patch is yet confirmed.

Technical Analysis

The vulnerability belongs to the broken access control class, specifically CWE-862 — Missing Authorization. In such flaws, the application fails to verify that the principal making a request possesses the required privileges before executing a sensitive operation. For a map-management plugin such as Ultimate Maps by Supsystic, this class of bug typically affects operations that manage map configurations, stored location data, settings, or other plugin-stored content. The component responsible for these operations is reachable through the public-facing HTTP interface and does not enforce a session or permission check, meaning the request is processed identically whether it originates from an authenticated administrator or an anonymous internet user.

The NVD description is intentionally sparse and does not disclose the specific handler names, HTTP endpoints, or request parameters involved. From the CVSS vector — AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H:A:N — several important technical conclusions can be drawn. First, the attack is network-based and low complexity, requiring no special conditions beyond reaching the web application. Second, no privileges and no user interaction are required, confirming the access control check is missing at the entry point rather than being bypassed through a logic flaw. Third, the scope is unchanged (U), meaning the compromise is confined to the plugin’s data plane. Fourth, confidentiality impact is none (C:N): the flaw does not appear to allow reading sensitive data directly. Fifth, integrity impact is high (I:H): an attacker can modify or overwrite plugin-managed data, map definitions, and site-embedded content. Finally, availability impact is none (A:N), suggesting the attacker cannot directly take the service offline, although corrupted map data could degrade functionality indirectly.

The product is publicly documented as a content management system plugin, most commonly WordPress, distributed under the Supsystic brand. In such architectures, unauthenticated reachability of plugin handlers is a recurring root cause: plugin developers frequently register AJAX or admin endpoints with missing capability checks, or expose configuration routines without verifying a valid nonce and user role. While the exact vulnerable routine is undisclosed, the vulnerability mechanism is consistent with an HTTP request reaching a state-changing function without an authorization gate. Because the integrity impact is rated high rather than low, the affected operation likely allows arbitrary modification of plugin data rather than merely changing a cosmetic preference.

Exploitation Scenarios

No public proof-of-concept, exploit code, or Nuclei template is available for CVE-2026-73377 at the time of writing. Given the homogeneity of the vulnerability class, the attack chain can be inferred with high confidence from the NVD description and CVSS metrics, although specific endpoint details remain unknown.

1. Reconnaissance and target identification. An attacker first identifies websites running Ultimate Maps by Supsystic. Common fingerprinting techniques include inspecting page source for map-rendering script identifiers, probing for the plugin’s asset directory or readme file, and using web search engines or passive DNS/HTTP inventory services to enumerate hosts. Shodan queries such as http.html:"supsystic" or http.title:"Ultimate Maps" can surface candidate targets. Version identification is performed by requesting the plugin’s static assets or metadata files, which typically embed a version string; instances reporting a version below 1.5.0 are vulnerable.

2. Triggering the access control flaw. With the target identified, the attacker sends crafted HTTP requests to the plugin’s exposed handler without supplying any authentication cookie, session token, or capability proof. Because the authorization check is missing, the application reaches the state-changing code path instead of returning an authentication error or redirect. The request is functionally identical to one issued by a legitimate administrator, minus the authentication context — the exact defect described by CWE-862 and by the NVD description’s “Unauthenticated Broken Access Control” phrasing.

3. Payload and execution method. The payload is delivered as part of the HTTP request body or query parameters at the vulnerability-class level: an unauthenticated POST/PUT request carrying map configuration data, location records, or settings fields that the plugin persists to its storage layer. Since no specific method name or parameter is documented, the payload is best described as “any state-changing parameter set accepted by the vulnerable plugin routine.” The server processes the input with the same trust level as an authenticated administrator, writing the attacker-controlled values into the site database.

4. Post-exploitation impact. A successful attack results in unauthorized modification of the plugin’s stored data. An attacker could replace map markers with malicious coordinates, alter embedded map titles and descriptions, inject arbitrary HTML/JavaScript into rendered map panels (a stored-XSS precondition), or reset plugin configuration. In the worst case, corrupted map data degrades the site experience for all visitors, and injected script content could subsequently be used to steal administrator sessions or redirect users to phishing pages, compounding the integrity compromise into a broader web infection. No confidentiality or direct denial-of-service impact is indicated by the CVSS subscores.

Impact Assessment

The business impact of CVE-2026-73377 is concentrated in data integrity. The CVSS base score of 7.5 reflects a high-severity, network-exploitable flaw with no credential or interaction requirements, placing any public-facing site running the plugin in the immediate risk zone. Affected systems include all deployments of Ultimate Maps by Supsystic with versions below 1.5.0, irrespective of hosting provider or operating system, since the flaw is in the application layer.

The blast radius is significant for organizations that use the plugin to render interactive maps for store locators, logistics tracking, event venues, or franchise directories. Tampering with location data can misdirect customers, damage brand credibility, and create operational confusion — for example, by altering clinic hours, delivery zones, or emergency contact pins. A secondary concern is the injection of scriptable content into map panels: if the plugin renders stored values without sanitization, an attacker who exploits this CVE may establish persistent client-side payloads that execute in the browsers of site visitors, enabling credential harvesting, malvertising, or drive-by downloads.

The integrity-only score (I:H, C:N, A:N) indicates that attackers obtain write access but not direct read access or outright denial of service. However, integrity compromises are frequently a stepping stone: tampered plugin data can be leveraged for stored XSS, which then restores the confidentiality and availability impacts the CVSS vector excludes. From a compliance perspective, unsanitized modification of publicly displayed business information could trigger disclosure obligations if the defacement affects regulated content such as price lists, health information, or financial service locators. Organizations should treat any confirmed exploitation as a security incident requiring forensic review of the plugin database tables and surrounding web application logs.

Detection Guidance

The detections below are anchored to the plugin identifiers that appear in the NVD description (“Supsystic”, “Ultimate Maps”) and to generic web-layer signals: unauthenticated, state-changing HTTP requests targeting the plugin. Because the exact vulnerable endpoint is undisclosed, operators should treat these rules as heuristic detection, tune them to their reverse-proxy and authentication logging, and validate alerts against baseline plugin administration traffic.

Sigma Rule

title: CVE-2026-73377 - Unauthenticated Access to Supsystic Ultimate Maps
id: 6c2a4f3b-9e1d-4a0b-8f5c-2b1d9e7a4c31
status: experimental
description: Detects HTTP requests from unauthenticated clients that reference the Ultimate Maps by Supsystic plugin and use state-changing methods, potentially indicating exploitation of CVE-2026-73377 (missing authorization, CWE-862).
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-73377
author: Valters IT Threat Intelligence
date: 2026/05/12
logsource:
    category: webserver
    product: generic
detection:
    selection_plugin:
        cs-uri-query|contains:
            - "supsystic"
            - "ultimate-maps"
    selection_method:
        cs-method:
            - POST
            - PUT
            - DELETE
    filter_authenticated:
        cs-cookie|contains:
            - "wordpress_logged_in"
    condition: selection_plugin and selection_method and not filter_authenticated
falsepositives:
    - Authenticated administrative requests when session cookies are not captured in the log source
    - Reverse proxies rewriting or stripping cookie headers
level: high

YARA Rule

rule CVE_2026_73377_Supsystic_Ultimate_Maps
{
    meta:
        author = "Valters IT Threat Intelligence"
        description = "Detects scripts, payloads, or plugin artifacts referencing the Ultimate Maps by Supsystic plugin, potentially associated with CVE-2026-73377 exploitation artifacts."
        cve = "CVE-2026-73377"
        cwe = "CWE-862"
        date = "2026-05-12"
        score = 75
    strings:
        $s1 = "ultimate-maps" nocase ascii
        $s2 = "supsystic" nocase ascii
        $s3 = "Ultimate Maps" nocase ascii
        $s4 = "maps-by-supsystic" nocase ascii
    condition:
        uint16(0) == 0x5A4D or filesize < 2MB
        and 2 of ($s*)
}

Suricata IDS Rule

alert http any any -> $HOME_NET any (msg:"CVE-2026-73377 - Unauthenticated Supsystic Ultimate Maps access attempt"; flow:established,to_server; content:"supsystic"; http.uri; nocase; content:"ultimate-maps"; http.uri; nocase; distance:0; within:100; http.method; content:"POST"; offset:0; nocase; classtype:attempted-admin; sid:202673377; rev:1; reference:cve,2026-73377;)

Elastic Detection

sequence by source.ip with maxspan=1m
  [ network where network.protocol == "http" and
    url.path like "*supsystic*" and
    url.path like "*ultimate-maps*" and
    http.request.method in ("POST", "PUT", "DELETE") ]
  [ network where network.protocol == "http" and
    url.path like "*supsystic*" and
    url.path like "*ultimate-maps*" and
    http.request.method in ("POST", "PUT", "DELETE") ]

The sequence fires when the same source IP issues repeated state-changing requests to the plugin within one minute, a pattern consistent with automated exploitation or mass probing rather than a single administrative action.

Splunk SPL Query

index=web sourcetype=access_combined
    (uri_path="*supsystic*" OR uri_path="*ultimate-maps*")
    AND method IN ("POST", "PUT", "DELETE")
    AND NOT cookie="*wordpress_logged_in*"
| eval auth_state = if(match(cookie, "(?i)wordpress_logged_in"), "authenticated", "unauthenticated")
| search auth_state="unauthenticated"
| stats count min(_time) as first_seen max(_time) as last_seen by src_ip, uri, method, status
| where count >= 3
| sort - count

Wazuh OSSEC Rule

<group name="web,supsystic,cve-2026-73377,">
  <rule id="100377" level="10">
    <decoded_as>web</decoded_as>
    <match>supsystic|ultimate-maps</match>
    <regex offset="0">\s(POST|PUT|DELETE)\s</regex>
    <description>CVE-2026-73377: Unauthenticated state-changing request targeting Ultimate Maps by Supsystic plugin</description>
    <group>cve-2026-73377,attack.attempt,</group>
    <mitre>
      <id>T1190</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence for CVE-2026-73377 is 0/4, meaning no patch evidence was found in any tracked source — NVD, vendor channels, OSV package feeds, or third-party advisories. The NVD description states the flaw affects “< 1.5.0 versions,” implying that version 1.5.0 contains the fix; however, no official vendor advisory or upgrade artifact has been confirmed. Until an authoritative fix is verified, treat the plugin as unpatched.

1. Immediate mitigations.

   • If the Ultimate Maps plugin is not business-critical, disable or uninstall it on all internet-facing sites until a patched build is confirmed.
   • Deploy a web application firewall (WAF) rule that blocks or challenges unauthenticated state-changing HTTP requests (POST/PUT/DELETE) containing “supsystic” or “ultimate-maps” URI markers. Permit only authenticated administrative source IP ranges.
   • Restrict administrative access to the content management system using IP allowlists, VPN, or multi-factor authentication to reduce the window for reconnaissance and to constrain any downstream stored-XSS impact.
   • Review and back up the plugin’s database tables and configuration files so that unauthorized modifications can be rolled back quickly.

2. Patch and upgrade steps.

   • Monitor the Supsystic official channel and the NVD record for an advisory confirming the 1.5.0 fix. When available, upgrade the plugin to 1.5.0 or later in a staging environment first, verifying that map functionality and custom templates remain intact.
   • After upgrading, verify the installed plugin file hashes against the vendor’s published checksums and confirm the version string in both the plugin metadata and the WordPress admin dashboard.
   • Audit the site for prior compromise: search database tables for unexpected map entries, injected JavaScript, and unowned admin accounts; scan web server logs for the URI patterns above preceding the patch date.

3. Long-term hardening.

   • Establish a vulnerability management cadence that includes plugin inventory, automated CVE correlation, and defined remediation SLAs for high-severity unauthenticated flaws.
   • Apply the principle of least privilege to the CMS: disable unused plugins, remove unused admin accounts, and enforce strong authentication for every account capable of modifying site content.
   • Subscribe to CISA KEV and vendor security mailing lists to receive early warning when a CVE transitions from theoretical to exploited-in-the-wild. Although CVE-2026-73377 is not currently on the CISA KEV list, its low exploitation complexity makes it a likely candidate once a public PoC emerges.
   • Implement centralized logging with the detection rules above so that access-control events are visible across all web properties, enabling rapid triage if future variants or partial bypasses surface.

References

• NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2026-73377
• MITRE CWE-862 (Missing Authorization): https://cwe.mitre.org/data/definitions/862.html
• MITRE ATT&CK Technique T1190 — Exploit Public-Facing Application: https://attack.mitre.org/techniques/T1190/
• CISA Known Exploited Vulnerabilities Catalog (not currently listing CVE-2026-73377): https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• Supsystic Product Page (Ultimate Maps): https://supsystic.com/ (vendor advisory not yet published; monitor for 1.5.0 release notes)

No threat-actor campaigns, exploit-in-the-wild evidence, or public proof-of-concept for CVE-2026-73377 were identified in the provided data. All exploitation scenarios above are inferred from the vulnerability class and CVSS vector; specific endpoint names and payload structures remain undocumented at this time.