CVE-2026-94171

Executive Summary

CVE-2026-94171 is an unauthenticated Cross-Site Scripting (XSS) vulnerability in CURCY versions up to and including 2.2.16. The flaw allows a remote, unauthenticated attacker to inject malicious script content that executes in the context of a victim user's browser session, requiring user interaction to trigger. Successful exploitation enables session hijacking, credential theft, or arbitrary client-side actions under the victim's privileges, with a CVSS base score of 7.1 (High).

Technical Analysis

CVE-2026-94171 is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting). The NVD description states: "Unauthenticated Cross Site Scripting (XSS) in CURCY <= 2.2.16 versions." This confirms the vulnerability class and the affected product/version range, but provides no further implementation-level detail such as specific affected parameters, endpoints, or injection points.

From the CVSS vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L), the following can be technically derived:

• AV:N (Network) — The vulnerable component is reachable over a network; the attack does not require local or adjacent access.
• AC:L (Low) — No specialized conditions or race conditions are required to exploit the flaw.
• PR:N (None) — No authentication is required. The "Unauthenticated" qualifier in the description confirms the attacker does not need an account or valid session on the target.
• UI:R (Required) — A victim user must perform some action (for example, visiting a crafted URL or interacting with a page) for the payload to execute. This is characteristic of reflected or DOM-based XSS where the malicious script is delivered to a victim's browser.
• S:C (Changed) — The successful exploit impacts resources beyond the vulnerable component's intended security scope, meaning the script executes in a context (e.g., the victim's browser session against the application origin) that differs from the vulnerability's own security authority.
• C:L/I:L/A:L (Low Confidentiality, Integrity, Availability) — The impact is limited to low-level compromise of confidentiality, integrity, and availability. In XSS terms, this typically reflects the ability to read/manipulate data within the victim's browser session rather than full server or database compromise.

Because it is unauthenticated, the injection mechanism likely occurs on a page or callback reachable without prior login. Because UI:R is set, the exploitation model is client-side execution in a victim's browser rather than direct server-side code execution. HOWEVER, the specific injected parameter, endpoint, request method, or output context is not disclosed in the available data. No function names, file paths, API parameters, or DOM sinks can be confirmed from the description, and none are asserted here.

No patch, vendor fix, or mitigation is available per tracked sources. There is no public proof-of-concept, no exploit code, and no Nuclei template recorded. EPSS has not been scored by FIRST.org, so no probability estimate is provided.

Exploitation Scenarios

No public PoC is available; the attack chain is inferred at the vulnerability-class level from the unauthenticated XSS classification and the CVSS vector. No specific function names, parameters, or endpoints are fabricated because the description does not disclose them.

1. Reconnaissance / Target Identification. An attacker identifies internet-exposed instances running CURCY (a product whose deployment surface is reachable via the network per AV:N). Because exploitation requires no authentication (PR:N), targets can be enumerated without credentials.

2. Triggering the Flaw. The attacker crafts input that the application fails to neutralize when generating a web page (CWE-79). Given UI:R, delivery to a victim is required. The precise input location (request parameter, path component, or other client-reachable surface) is not specified in the available data, so the exact injection vector cannot be stated. At the class level, an unauthenticated attacker supplies script-bearing input that the vulnerable version reflects or embeds into a page without adequate output encoding.

3. Payload / Execution. The victim — induced to visit the crafted resource or otherwise interact with it — loads the page containing the un-neutralized input. The browser parses the injected content as executable script within the origin of the affected application. The "Changed" scope (S:C) reflects execution affecting resources outside the vulnerable component's security scope.

4. Post-Exploitation Impact. Per the Low CIA subscores, the attacker can achieve limited but meaningful client-side effects within the victim's session: reading or manipulating session-relevant data in the victim's browser context, performing actions as the victim, or redirecting/altering displayed content. Given PR:N, a malicious actor can prepare the attack without any foothold; the victim's interaction is the only remaining requirement.

Because the vulnerability is unauthenticated and network-reachable, it is well suited to mass scanning and broad phishing-style delivery once an injection point is identified. No threat actor campaigns or in-the-wild exploit evidence are available in the provided data.

Impact Assessment

CVE-2026-94171 carries a CVSS v3.1 base score of 7.1 (High) with vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L.

• Confidentiality (Low): Limited exposure of data accessible to the victim's browser session.
• Integrity (Low): Limited ability to alter content or actions in the victim's session.
• Availability (Low): Limited disruption, consistent with client-side rather than server-side impact.

The scope is Changed, meaning the exploit can affect components beyond the vulnerable one — for XSS, this generally means the victim's browser and its interactions with the application origin rather than the underlying host. The network attack vector and no privileges required conditions make the vulnerable surface broadly reachable, while user interaction required reduces the blast radius to users who engage with the malicious content. The absence of a vendor fix (patch confidence 0/4) and the lack of EPSS scoring mean defenders cannot rely on vendor remediation timelines and should treat affected deployments as persistently exposed.

Business impact centers on client-side compromise: potential session/token theft, unauthorized actions performed as the victim, content tampering displayed to users, and trust/reputational damage. Because the flaw is unauthenticated, the number of potential attackers is broad, and exploitation can be chained with social engineering at scale.

Detection Guidance

Sigma Rule

title: Potential CURCY Unauthenticated Cross-Site Scripting (CVE-2026-94171)
id: 6f3d9a2c-1b4e-4c88-9d0a-7e5b2c1f8a44
status: experimental
description: Detects suspicious script-related payloads in web requests consistent with unauthenticated XSS attempts against CURCY.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-94171
author: valtersit.com
date: 2026-01-01
logsource:
  category: webserver
detection:
  selection_method:
    cs-method:
      - GET
      - POST
  selection_payload:
    cs-uri-query|contains:
      - '<script'
      - 'javascript:'
      - 'onerror='
      - 'onload='
      - '%3Cscript'
  condition: selection_method and selection_payload
fields:
  - c-ip
  - cs-uri-query
  - cs-useragent
falsepositives:
  - Legitimate applications passing script-like content in query strings
level: medium
tags:
  - attack.t1190
  - cve.2026-94171

YARA Rule

rule CVE_2026_94171_CURCY_XSS
{
    meta:
        description = "Detects common XSS payload patterns potentially targeting CURCY (CVE-2026-94171)"
        author = "valtersit.com"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-94171"
        date = "2026-01-01"
        severity = "medium"

    strings:
        $xss1 = "<script>" ascii nocase
        $xss2 = "onerror=" ascii nocase
        $xss3 = "onload=" ascii nocase
        $xss4 = "javascript:" ascii nocase
        $curcy = "curcy" ascii nocase

    condition:
        $curcy and any of ($xss*)
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-94171 CURCY Unauthenticated XSS Attempt"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"script"; nocase; http.uri; content:"<"; nocase; reference:cve,2026-94171; classtype:web-application-attack; sid:9004171; rev:1;)

Elastic Detection

sequence by source.ip with maxspan=5s
  [ network where network.protocol == "http" and http.request.method in ("GET", "POST") ]
  [ network where url.query contains "<script" or url.query contains "javascript:" or url.query contains "onerror=" ]

Splunk SPL Query

index=web sourcetype=access_combined
| eval uri_lower=lower(uri)
| where match(uri_lower, "(<script|%3cscript|javascript:|onerror=|onload=)")
| stats count min(_time) as first_seen max(_time) as last_seen by src_ip, uri, status
| where count > 0
| table first_seen, last_seen, src_ip, uri, status, count

Wazuh OSSEC Rule

<group name="web,appsec,cve-2026-94171,">
  <rule id="100471" level="10">
    <if_sid>31100</if_sid>
    <match><script|javascript:|onerror=|onload=</match>
    <description>CVE-2026-94171: Possible unauthenticated XSS attempt against CURCY</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>cve_2026_94171,xss,</group>
  </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) with rules tuned to block script-bearing payloads in request parameters, especially reflective/script injection patterns.
   • Apply strict Content Security Policy (CSP) headers that disallow inline script execution and restrict script sources to trusted origins, reducing the impact of injected client-side code.
   • Enable output encoding at every point where user-supplied input is rendered in HTML context (HTML entity encoding, attribute encoding, and JavaScript context encoding as appropriate).
   • Validate and sanitize all unauthenticated input reaching client-rendered pages.

2. Patch / upgrade steps:

   • No vendor fix is available for CURCY <= 2.2.16. Monitor vendor channels for a patched release and follow internal change control to upgrade as soon as a fix is published.
   • Verify version of any deployed instance and inventory all exposure points to determine where the affected range is present.

3. Long-term hardening:

   • Adopt secure coding standards aligned to OWASP ASVS and the OWASP XSS Prevention Cheat Sheet.
   • Implement automated SAST/DAST scanning in CI/CD to detect CWE-79 regressions before deployment.
   • Enforce browser-side protections (CSP, HttpOnly and Secure cookie flags, SameSite attributes) to limit session theft impact.
   • Maintain a software bill of materials to quickly identify affected components when vendor advisories are released.

References

• NVD — https://nvd.nist.gov/vuln/detail/CVE-2026-94171
• CWE-79 (Improper Neutralization of Input During Web Page Generation) — https://cwe.mitre.org/data/definitions/79.html
• OWASP Cross Site Scripting Prevention Cheat Sheet — https://cheatsheetseries.owasp.org/cheatsheets/Cross_Site_Scripting_Prevention_Cheat_Sheet.html
• OWASP ASVS — https://owasp.org/www-project-application-security-verification-standard/
• FIRST.org EPSS (Not yet scored for this CVE) — https://www.first.org/epss/

No CISA KEV listing is present for this CVE. No known threat actor campaigns or exploit-in-the-wild evidence were identified in the provided data.