CVE-2026-62049

Executive Summary

CVE-2026-62049 is a stored cross-site scripting (XSS) vulnerability in the WordPress plugin JetBlocks For Elementor, developed by Crocoblock, affecting all versions through 1.5.2.1. An authenticated attacker with low privileges can inject persistent script content that is later rendered to other users in the context of their browser session. Successful exploitation enables session theft, credential harvesting, and arbitrary actions performed as the victim within the affected WordPress site.

Technical Analysis

The vulnerability is classified under CWE-79, Improper Neutralization of Input During Web Page Generation, specifically the stored (persistent) variant. Stored XSS occurs when user-supplied input is persisted by the application — typically into a database, post meta field, or plugin-configured option — and is subsequently emitted into HTML output without adequate output encoding or contextual escaping.

JetBlocks For Elementor is a WordPress plugin that extends the Elementor page builder with additional widgets and block components. Elementor widget data is stored as structured content in WordPress and rendered on the front end and, in some configurations, within the administrative editor preview. The CVE record confirms the vulnerable component is the plugin itself and enumerates affected versions as "from n/a through 1.5.2.1," meaning no fixed version exists at the time of publication.

The CVSS 3.1 vector is AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L. Three elements are operationally significant:

• PR:L indicates the attacker requires an authenticated account on the target WordPress site. In default WordPress configurations, the Subscriber role is the lowest authenticated tier and is commonly self-registrable on sites with open registration. Contributor and Author roles are also sufficient and carry more capability.
• UI:R indicates exploitation requires interaction from a second party. Because the payload is stored, this interaction occurs when a victim — frequently an administrator reviewing content, or a front-end visitor — loads the page that renders the injected content.
• S:C (Changed Scope) indicates the vulnerability crosses a trust boundary. Script injected through the plugin's render path executes in the origin of the WordPress site, granting the payload access to cookies, tokens, and authenticated state of any user viewing the page. This is why the confidentiality and integrity impacts are scored Low individually but the scope change elevates overall severity to 6.5 (Medium).

No public proof-of-concept, Nuclei template, or exploit code exists for this CVE. The specific input vector — the exact widget field, AJAX action, REST route, or shortcode attribute through which the unescaped parameter passes — is not disclosed in the NVD description. Any claim about a specific parameter name would be speculation and is deliberately omitted here. What can be stated with confidence from the vulnerability class alone is the general mechanism: a plugin-supplied field accepts and stores markup, and the plugin's output path does not sanitize or escape it before injection into the page.

Exploitation Scenarios

This section describes the attack chain at the vulnerability-class level. No public PoC is available; the following is inferred from stored XSS mechanics and the CVSS vector, not from a published exploit.

1) Reconnaissance and target identification An attacker identifies WordPress sites running JetBlocks For Elementor at version 1.5.2.1 or earlier. Identification is passive: plugin assets referenced in front-end HTML, readme.txt metadata reachable over HTTP, or fingerprinting services that enumerate installed components. The attacker confirms whether the site permits self-registration or whether the attacker already holds credentials from prior access.

2) Triggering the flaw class Stored XSS requires a write path and a read path. The write path is an authenticated request that submits markup into a field persisted by the plugin. The read path is the render of a page or preview that outputs that stored value. The attacker authenticates — with a self-registered low-privilege account or a compromised credential — and submits content containing script markup through the plugin's user-facing input surface. Because the plugin does not neutralize the input on storage or on output, the markup survives into the rendered page.

3) Payload and execution The payload resides in stored content. It executes when any user loads the affected page or editor preview. At the vulnerability-class level, the payload is JavaScript executing in the site's origin. It can read the DOM, access the victim's cookies that lack HttpOnly protection, retrieve any nonce embedded in the page, and issue same-origin requests that inherit the victim's authenticated session.

4) Post-exploitation Using the victim's authenticated context, the payload can perform state-changing actions available to the victim's role. If the victim is an administrator — a realistic outcome given that admins routinely preview and moderate content — the attacker can create additional administrator accounts, alter plugin and theme settings, install malicious plugins, or modify content. Persistent script injection also supports long-dwell credential harvesting and redirection of site visitors to attacker-controlled infrastructure. The Changed Scope metric reflects that the compromise is not confined to the low-privilege attacker's own account and propagates to any user who views the tainted page.

Impact Assessment

The CVSS 3.1 base score is 6.5 (Medium), vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L. Interpretation of the subscores:

• Attack Vector Network and Attack Complexity Low: exploitation is remotely reachable and, once the injection point is known, requires no special conditions. The injection point itself is currently undisclosed, which is the principal practical barrier.
• Privileges Required Low: the attacker needs at least a basic authenticated account, a low bar on sites with open registration.
• User Interaction Required: the payload fires only when a victim loads the affected page. This is the throttling factor on exploitation.
• Scope Changed: the vulnerability's impact extends beyond the vulnerable component into the surrounding application origin and its users, which is what drives the elevated composite score despite Low individual impacts.
• Confidentiality, Integrity, Availability Low: session data exposure and content modification are expected; no direct denial of service is implied by the vector.

Business impact concentrates on WordPress sites using JetBlocks For Elementor. Realistic consequences include administrative account takeover via a hijacked admin session, defacement, injection of malicious redirects or third-party scripts affecting site visitors, and SEO poisoning. For organizations subject to regulatory obligations, unauthenticated or account-level injection of script into site pages can constitute a personal data exposure if visitor sessions or submitted form data are captured. Blast radius extends to every user who views an affected page, not merely the content author. EPSS has not been scored by FIRST.org for this CVE; no exploitation likelihood estimate is available, and no evidence of in-the-wild exploitation or CISA KEV listing exists at the time of writing.

Detection Guidance

Sigma Rule

title: Possible Stored XSS Injection Attempt Against JetBlocks for Elementor
id: 8f3c1a92-4d7e-4b2a-9c11-jetblock62049
status: experimental
description: Detects authenticated requests containing script markup directed at JetBlocks for Elementor plugin endpoints, consistent with stored XSS injection attempts (CVE-2026-62049).
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-62049
author: Threat Intelligence
date: 2026/01/01
tags:
  - attack.t1059.007
  - cwe.79
logsource:
  category: webserver
detection:
  selection_method:
    cs-method:
      - POST
      - PUT
  selection_target:
    cs-uri-query|contains:
      - 'jet-blocks'
      - 'jetblocks'
  selection_payload:
    cs-uri|contains:
      - '<script'
      - '%3Cscript'
      - 'onerror='
      - 'onload='
      - 'javascript:'
      - '<svg'
      - '<img'
  condition: selection_method and selection_target and selection_payload
fields:
  - c-ip
  - cs-uri
  - cs-method
  - sc-status
falsepositives:
  - Legitimate content authors embedding sanitized markup in posts
  - Security scanners and WAF test traffic
level: medium

YARA Rule

rule CVE_2026_62049_JetBlocks_Stored_XSS
{
    meta:
        description = "Detects JetBlocks for Elementor plugin files potentially affected by CVE-2026-62049 stored XSS, and stored XSS payload artifacts in cached/templated content"
        author = "Threat Intelligence"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-62049"
        date = "2026-01-01"
        severity = "medium"

    strings:
        $plugin_a = "JetBlocks For Elementor" ascii nocase
        $plugin_b = "jet-blocks" ascii nocase
        $plugin_c = "jetblocks" ascii nocase
        $ver = "1.5.2.1" ascii

        $xss1 = "<script" ascii nocase
        $xss2 = "</script>" ascii nocase
        $xss3 = "onerror=" ascii nocase
        $xss4 = "onload=" ascii nocase
        $xss5 = "javascript:" ascii nocase
        $xss6 = "document.cookie" ascii nocase
        $xss7 = "eval(" ascii nocase
        $xss8 = "<svg/onload" ascii nocase

    condition:
        (any of ($plugin_*)) and
        (
            (any of ($xss1, $xss2, $xss3, $xss4, $xss5, $xss8)) or
            (2 of ($xss6, $xss7))
        )
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-62049 JetBlocks for Elementor Stored XSS Injection Attempt"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"jet-blocks"; nocase; http.request_body; content:"<script"; nocase; http.request_body; content:"</script>"; nocase; reference:cve,2026-62049; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-62049; classtype:web-application-attack; sid:202662049; rev:1;)

alert http any any -> any any (msg:"CVE-2026-62049 JetBlocks for Elementor Stored XSS Event Handler Injection"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"jet-blocks"; nocase; pcre:"/(?:onerror|onload|onmouseover)\s*=/i"; reference:cve,2026-62049; classtype:web-application-attack; sid:202662050; rev:1;)

Elastic Detection

sequence by source.ip, user.name with maxspan=30s
  [ network where network.protocol == "http" and
      http.request.method == "POST" and
      stringContains(http.request.body, "jet-blocks") ]
  [ network where network.protocol == "http" and
      http.request.method == "POST" and
      (stringContains(http.request.body, "<script") or
       stringContains(http.request.body, "javascript:") or
       stringContains(http.request.body, "onerror=") or
       stringContains(http.request.body, "onload=")) ]

Splunk SPL Query

index=web sourcetype=access_combined OR sourcetype=nginx:plus:access
| eval uri_lower = lower(uri)
| eval body_lower = lower(coalesce(form_data, request_body, ""))
| where match(uri_lower, "jet-?blocks")
| where (match(body_lower, "<script") OR match(body_lower, "javascript:") OR match(body_lower, "onerror\s*=") OR match(body_lower, "onload\s*=") OR match(body_lower, "<svg"))
| stats count min(_time) as first_seen max(_time) as last_seen values(uri) as uris values(status) as statuses by src_ip, user, host
| where count >= 1
| convert ctime(first_seen) ctime(last_seen)
| sort - count

Wazuh OSSEC Rule

<group name="web,appsec,wordpress,">
  <rule id="100620" level="10">
    <if_sid>31100,31103,31104</if_sid>
    <url>jet-blocks|jetblocks</url>
    <regex type="pcre2">&lt;script|\x3Cscript|javascript:|onerror\s*=|onload\s*=|\x3Csvg</regex>
    <description>CVE-2026-62049: Possible stored XSS injection attempt against JetBlocks for Elementor plugin</description>
    <mitre>
      <id>T1059.007</id>
    </mitre>
    <group>cve_2026_62049,stored_xss,</group>
  </rule>

  <rule id="100621" level="12">
    <if_sid>100620</if_sid>
    <regex type="pcre2">document\.cookie|XMLHttpRequest|fetch\(|eval\(</regex>
    <description>CVE-2026-62049: JetBlocks XSS payload contains session-exfiltration primitives</description>
    <group>cve_2026_62049,stored_xss,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source). There is no vendor fix, no workaround published by the vendor, and no affected-version package data enumerated beyond the version ceiling of 1.5.2.1 stated in the NVD description.

Immediate mitigations Given no patch exists, compensating controls are the primary defense:

• Restrict or disable open user registration on all WordPress instances running the affected plugin, which removes the lowest-barrier path to the PR:L prerequisite.
• Audit user roles and enforce least privilege. Convert unnecessary Contributor/Author accounts to Subscriber, and remove dormant accounts.
• Deploy a web application firewall with XSS inspection on the plugin's input paths. Virtual patching at the WAF layer is the closest available substitute for a vendor fix.
• Enforce HttpOnly and Secure flags on session cookies site-wide, and implement a strict Content-Security-Policy that blocks inline script. CSP does not remove the injection but materially reduces payload execution.
• Set the WordPress X-Content-Type-Options: nosniff header and ensure all admin interfaces are behind authentication with MFA to limit post-exploitation account takeover.

Patch and upgrade steps

• Monitor the Crocoblock vendor channel and the WordPress plugin repository for a fixed release above 1.5.2.1. No fixed version is available today; any version at or below 1.5.2.1 should be treated as vulnerable.
• If the plugin is not operationally required, deactivate and remove it. This eliminates the attack surface entirely and is the only complete mitigation in the absence of a patch.
• If a fix is released, stage and test in a non-production environment, then update. After updating, re-scan stored content for residual injected markup, since patching the render path does not clean already-persisted payloads.

Long-term hardening

• Maintain an inventory of WordPress plugins and subscribe to vulnerability feeds so affected components are identified before exploitation.
• Adopt a vulnerability management workflow with SLAs for unpatched third-party components.
• Enforce content sanitization on all user-submitted fields at the application layer and validate output encoding in custom theme and plugin code.
• Enable audit logging on WordPress content operations and centralize logs for review.

References

• NVD — CVE-2026-62049: https://nvd.nist.gov/vuln/detail/CVE-2026-62049
• MITRE CWE-79 — Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'): 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
• WordPress Plugin Security documentation: https://developer.wordpress.org/plugins/security/
• Crocoblock JetBlocks For Elementor product page (vendor channel for patch notification): https://crocoblock.com/plugins/jetblocks/

No threat actor campaign, exploit-in-the-wild evidence, or CISA KEV entry is associated with CVE-2026-62049 at the time of writing. No public proof-of-concept, Nuclei template, or exploit code is available.