CVE-2026-102258

Executive Summary

CVE-2026-102258 is a post-authentication stored cross-site scripting (XSS) vulnerability in the SMA1000 Appliance Management Console (AMC). According to the NVD description, an attacker who is authenticated as an administrator can, under specific conditions, store and potentially execute arbitrary JavaScript code within the console. Because exploitation requires administrator privileges, the primary impact is session abuse or malicious script execution against other privileged users interacting with the affected console, not unauthenticated remote compromise.

Technical Analysis

The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation, i.e., Cross-Site Scripting) with a stored (persistent) subtype, per the NVD description. In a stored XSS flaw, attacker-supplied input is persisted by the application — for example to a database or configuration store — and later rendered without adequate output encoding or sanitization when another user views the affected content. The malicious JavaScript then executes in the victim's browser in the security context of the AMC origin.

The affected component is the SMA1000 Appliance Management Console (AMC), the administrative web interface for SonicWall SMA1000 secure access appliances. The NVD description states the issue is "post-authentication" and that the actor must be "authenticated attacker as administrator," which indicates the vulnerable input is accepted via an administrative function of the console. The exact injection point, storage location, and rendering endpoint are not disclosed in the available data; no specific parameter, file path, or function is provided, so the precise code-level mechanism cannot be stated without fabrication.

The CVSS v3.1 vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N) merits careful reading, as it appears partially inconsistent with the "administrator authenticated" wording in the description. The vector reflects: network attack vector, low attack complexity, no privileges required per the metric, and user interaction required — consistent with a victim needing to view a page containing the stored payload. Scope is Changed (S:C) and confidentiality/integrity impacts are Low (C:L/I:L), with no availability impact (A:N). The PR:N component in the vector is unusual given the description's "post-authentication" framing; consumers should treat the CVSS vector as published by the scoring source and reconcile it with the NVD narrative, which clearly requires an authenticated administrative actor to plant the payload.

Because JavaScript executed via stored XSS runs under the AMC origin, the attack surface is the browser session of any user — including other administrators or delegated operators — who subsequently views the injected content. The provided data does not identify the specific vulnerable AMC page, input field, or storage mechanism.

Exploitation Scenarios

No public proof-of-concept, exploit code, or Nuclei template is available for CVE-2026-102258. The attack chain below is inferred strictly from the vulnerability class (stored XSS), the CVSS vector, and the NVD description. The specific injection point and payload-delivery endpoint are not disclosed in the available data and are not fabricated here.

1. Reconnaissance / target identification. The attacker identifies an exposed SMA1000 Appliance Management Console reachable over the network. Because exploitation is post-authentication, the attacker must already hold — or have obtained — administrative credentials for the AMC. The reconnaissance value here is identifying which administrative interface is reachable and which fields within it accept and persist input that later renders to other users.

2. Triggering the flaw class. The attacker, authenticated as administrator, supplies crafted input into a console feature that stores data and later renders it. In a stored XSS, the payload is not reflected immediately; it is persisted server-side and executed when the stored content is displayed. Based on the NVD description, "specific conditions" are required for the stored content to be rendered and executed.

3. Payload / execution at the class level. The injected content is JavaScript. When another user loads the page that renders the stored value, the script executes in that user's browser within the AMC origin. At the class level, common objectives for such payloads are executing script in the victim's session context, performing actions as the victim, or exfiltrating data reachable from the browser. No specific payload, parameter, or endpoint is documented, and none is asserted here.

4. Post-exploitation impact. Per the CVSS vector, the confidentiality and integrity impacts are Low, with scope Changed — meaning the vulnerable component's exploitation can affect resources beyond its original security scope (for example, other users' browser sessions). The description states the actor can "store and potentially execute arbitrary JavaScript code in the AMC." Practical consequences consistent with stored XSS in an administrative console include execution of script in the context of other users who view the injected content and actions taken under those users' sessions. Specific data-exfiltration or privilege-escalation outcomes are not documented in the provided data.

Impact Assessment

CVE-2026-102258 affects the SMA1000 Appliance Management Console. The impact is constrained by the required precondition that the attacker is authenticated as an administrator. This substantially reduces the unauthenticated attack surface relative to a pre-auth XSS or RCE, but it does not eliminate risk: administrative consoles are high-value targets, and a stored XSS flaw can be used against other privileged users who interact with the console, including users with different or greater privileges than the attacker in multi-admin deployments.

Mapping to the CVSS subscores: Attack Vector is Network (AV:N), so the vulnerable console can be reached remotely; Attack Complexity is Low (AC:L); User Interaction is Required (UI:R), consistent with a victim needing to view the stored content; Scope is Changed (S:C); and Confidentiality and Integrity impacts are Low (C:L/I:L) with no Availability impact (A:N). The base score is 6.1 (Medium). The EPSS score is not yet assigned by FIRST.org, and the CVE is not listed in CISA KEV, so there is currently no evidence of active exploitation in the wild.

Blast radius: any environment operating the affected SMA1000 AMC, particularly deployments with multiple administrative users or delegated operators where one administrator can plant content viewed by others. Because the exact affected version range is not disclosed in the available data, organizations should consult the vendor directly for version applicability rather than assume a range.

Detection Guidance

Sigma Rule

title: Stored XSS Payload Submission to SMA1000 Appliance Management Console
id: 7c1e9a24-3f5b-4a2e-9d61-102258a10f01
status: experimental
description: Detects HTTP requests containing common XSS payload patterns directed at the SMA1000 Appliance Management Console (CVE-2026-102258). Post-authentication stored XSS abusing administrative console input fields.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-102258
author: valtersit.com
date: 2026-01-01
logsource:
  category: webserver
  product: sonicwall
detection:
  selection_method:
    cs-method:
      - POST
      - PUT
      - PATCH
  selection_uri:
    cs-uri-stem|contains:
      - '/amc'
  selection_payload:
    cs-uri-query|contains:
      - '<script'
      - 'javascript:'
      - 'onerror='
      - 'onload='
      - 'document.cookie'
      - 'svg/onload'
  condition: selection_method and selection_uri and selection_payload
falsepositives:
  - Legitimate administrative input containing code samples
level: medium
tags:
  - attack.t1059.007
  - cwe.79

YARA Rule

rule CVE_2026_102258_SMA1000_Stored_XSS
{
    meta:
        description = "Detects stored XSS payload artifacts targeting the SMA1000 Appliance Management Console (CVE-2026-102258)"
        author = "valtersit.com"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-102258"
        date = "2026-01-01"
        severity = "medium"

    strings:
        $xss1 = "<script>" nocase ascii
        $xss2 = "<script " nocase ascii
        $xss3 = "javascript:" nocase ascii
        $xss4 = "onerror=" nocase ascii
        $xss5 = "onload=" nocase ascii
        $xss6 = "document.cookie" nocase ascii
        $amc  = "Appliance Management Console" ascii wide
        $sma  = "SMA1000" ascii wide

    condition:
        (2 of ($xss*)) and (any of ($amc, $sma))
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-102258 SMA1000 AMC Stored XSS Payload Attempt"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/amc"; nocase; http.request_body; content:"<script"; nocase; sid:1022581; rev:1; metadata:created_at 2026_01_01, cve CVE-2026-102258, cwe CWE-79; classtype:web-application-attack;)
alert http any any -> any any (msg:"CVE-2026-102258 SMA1000 AMC XSS Event Handler Payload"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/amc"; nocase; http.request_body; pcre:"/on(error|load|mouseover)\s*=/i"; sid:1022582; rev:1; metadata:created_at 2026_01_01, cve CVE-2026-102258, cwe CWE-79; classtype:web-application-attack;)

Elastic Detection

sequence by host.id, user.name with maxspan=5m
  [ network where event.action == "request" and
      network.protocol == "http" and
      http.request.method in ("POST", "PUT", "PATCH") and
      stringContains(http.request.body, "<script") ]
  [ network where event.action == "request" and
      network.protocol == "http" and
      stringContains(url.path, "/amc") and
      stringContains(http.response.body, "<script") ]

Splunk SPL Query

index=web sourcetype=access_combined
| eval uri=coalesce(uri, url, cs_uri_stem)
| where match(uri, "(?i)/amc")
| search (method=POST OR method=PUT OR method=PATCH)
| where match(_raw, "(?i)(<script|javascript:|onerror=|onload=|document\.cookie|svg/onload)")
| stats count min(_time) as first_seen max(_time) as last_seen values(clientip) as src_ips values(uri) as target_uris by user, dest
| sort - count

Wazuh OSSEC Rule

<group name="web,appsec,sonicwall,">
  <rule id="102258" level="10">
    <decoded_as>web-accesslog</decoded_as>
    <match>amc</match>
    <regex type="pcre2">(?i)(&lt;script|javascript:|onerror=|onload=|document\.cookie)</regex>
    <description>CVE-2026-102258: Possible stored XSS payload submitted to SMA1000 Appliance Management Console</description>
    <mitre>
      <id>T1059.007</id>
    </mitre>
    <group>cve_2026_102258,xss,</group>
  </rule>
</group>

Mitigation & Patch Guidance

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

1. Immediate mitigations. Restrict network exposure of the SMA1000 Appliance Management Console to trusted management networks or VPN-only access, and avoid exposing the AMC directly to the internet. Enforce least privilege among administrative accounts, minimize the number of users with AMC access, and audit any multi-admin or delegated-operator configuration where one user's stored input could be viewed by another. Because exploitation is post-authentication, hardening administrative credential hygiene and enabling MFA on administrator accounts reduces the precondition for abuse.

2. Patch/upgrade steps. No vendor fix or affected version range is available from tracked sources. The authoritative action is to contact SonicWall support or monitor the SonicWall security advisory channel for an official fix and the precise affected version list, then apply the vendor-recommended firmware/software update for the SMA1000 AMC. Do not assume applicability of a version range; obtain confirmation from the vendor.

3. Long-term hardening. Adopt output-encoding and input-validation controls at the application level where vendor updates provide them, deploy a web application firewall in front of the AMC with XSS-focused rulesets as a compensating control, enable content security policy headers if supported by the console, and maintain continuous monitoring of AMC access logs for stored-XSS payload patterns. Track the CVE for EPSS score assignment, any CISA KEV addition, and the emergence of public exploit code, since none exists at the time of writing.

References

• NVD — CVE-2026-102258: https://nvd.nist.gov/vuln/detail/CVE-2026-102258
• CWE-79 (Improper Neutralization of Input During Web Page Generation / Cross-Site Scripting): https://cwe.mitre.org/data/definitions/79.html
• SonicWall Security Advisories (vendor advisory channel — verify the SMA1000 AMC advisory directly): https://psirt.global.sonicwall.com/vuln-list
• MITRE ATT&CK T1059.007 (Command and Scripting Interpreter: JavaScript): https://attack.mitre.org/techniques/T1059/007/
• CISA Known Exploited Vulnerabilities Catalog (CVE-2026-102258 is not currently listed): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

No public PoC, exploit code, Nuclei template, threat actor campaign, or exploit-in-the-wild evidence is associated with CVE-2026-102258 in the available data. EPSS has not yet scored this CVE, and it is not in CISA KEV.