CVE-2026-106629

Executive Summary

CVE-2026-106629 is a stored Cross-Site Scripting (XSS) vulnerability in Adobe Experience Manager (AEM) that allows an attacker to inject malicious scripts into vulnerable form fields. Successful exploitation executes attacker-controlled JavaScript in the browser of any victim who views the affected page, potentially granting elevated access to or control over the victim's account or session. With a CVSS base score of 9.3 and a Changed scope (S:C), the impact can extend beyond the vulnerable component to other security authorities within the AEM deployment. No vendor patch, public proof-of-concept, or known exploitation activity has been confirmed at the time of this report.

Technical Analysis

The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting) and is specifically a stored XSS issue. Per the NVD description, the flaw resides in "vulnerable form fields" within Adobe Experience Manager: user-supplied input is persisted by the application and later rendered into a web page without adequate output encoding or sanitization, causing the injected markup/script to execute in the context of a subsequent visitor's browser session.

Key characteristics derivable from the available data:

• Storage and persistence: Unlike reflected XSS, the payload is stored server-side and is delivered to every user who browses to the affected page, raising the number of potential victims without requiring individual lure links.
• Trigger surface: Form fields within AEM are the injection point. The description does not enumerate specific component names, endpoints, or parameter identifiers, so the exact vulnerable fields cannot be named without fabrication. Additional technical implementation detail is not available in the provided intelligence.
• Scope Change (S:C): The CVSS vector specifies a changed scope, meaning exploitation may affect resources beyond the vulnerable component's own security authority — for example, impacting the broader AEM author/publish environment or the victim's authenticated session.
• Unauthenticated network attack with user interaction: AV:N/AC:L/PR:N indicate the attack is network-reachable, low-complexity, and requires no prior privileges on the attacker's side, but UI:R confirms a victim must interact (e.g., load the page rendering the stored payload).
• Confidentiality and Integrity: C:H/I:H with A:N indicate high confidentiality and integrity impact and no direct availability impact.

Because no exploit code, Nuclei template, or PoC exists, the concrete payload shape and exact injection vector cannot be confirmed and are not asserted here. The analysis remains at the vulnerability-class level, consistent with the CWE-79 definition.

Exploitation Scenarios

No public PoC is available; the attack chain below is inferred from the stored XSS vulnerability class and the NVD description. No specific function names, endpoints, or parameters are invented.

1. Reconnaissance / target identification. The attacker identifies an internet- or intranet-exposed AEM instance, including pages containing forms that accept and later display user input. Public asset-discovery techniques (search engine fingerprinting, Shodan/censys-style banner matching for AEM titles and content paths) can be used to locate candidate deployments.
2. Injection (triggering the flaw class). The attacker submits crafted input into a form field that the application persists and subsequently renders without proper output encoding. The absence of effective sanitization and output encoding allows script-bearing content to be stored in the application's data store (for example, as part of a stored form submission).
3. Payload delivery / execution. When any user navigates to the page that displays the vulnerable field, the stored markup is returned to the browser and interpreted as executable script. This is the defining behavior of a stored XSS payload — direct script execution in the victim's browser context. (Specific payload syntax is not asserted because no PoC is available.)
4. Post-exploitation impact. Depending on the victim's privileges and the scope of the affected origin, the executing script can perform authenticated actions as the victim, exfiltrate session tokens or page content, or otherwise manipulate the application on the victim's behalf. The S:C rating indicates the impact can cross trust boundaries within the AEM deployment, potentially affecting administrative or authoring interfaces. Because C:H and I:H are assigned, both data disclosure and unauthorized modification of application state are credible outcomes.

Impact Assessment

• Base severity: CVSS 3.1 base score 9.3 (Critical) — AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N.
• Confidentiality (High): Session tokens, application data, and page content within the victim's accessible scope can be exposed to the attacker.
• Integrity (High): The attacker can act within the victim's session, modifying content and state consistent with the victim's privileges.
• Availability (None): The vector assigns no availability impact.
• Scope (Changed): Exploitation may affect components or resources beyond the vulnerable form component, elevating risk for administrative and privileged users of the AEM environment.
• Blast radius: Any enterprise running Adobe Experience Manager with form fields that echo stored user input to other users is potentially affected. Because the issue is stored, one successful injection can impact many users over time, including authors and administrators who view the poisoned page.
• Business impact: Depending on which accounts are exposed, consequences can range from content defacement and data theft to session hijacking and, in severe cases, administrative compromise of the CMS — a high-value target for supply-chain-style content manipulation and phishing.

Detection Guidance

Sigma Rule

title: Potential Stored XSS Attempt Against Adobe Experience Manager Form Fields
id: 7f3c1b8e-2a44-4e9d-9c11-0a4b5d6e7f01
status: experimental
description: Detects script-bearing payload patterns submitted to AEM form endpoints and reflected in stored content
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-106629
author: valtersit.com
date: 2026/01/01
logsource:
  category: webserver
detection:
  selection_method:
    cs-method:
      - POST
      - PUT
  selection_uri:
    cs-uri-stem|contains:
      - '/content/'
      - '/forms/'
  selection_payload:
    cs-uri-query|contains:
      - '<script'
      - 'javascript:'
      - 'onerror='
      - 'onload='
      - '<svg'
      - 'onmouseover='
  condition: selection_method and selection_uri and selection_payload
fields:
  - c-ip
  - cs-uri-stem
  - cs-uri-query
  - cs-method
falsepositives:
  - Legitimate administrative content authoring
  - Security testing
level: high
tags:
  - attack.t1059.007
  - cve.2026.106629

YARA Rule

rule CVE_2026_106629_AEM_Stored_XSS
{
    meta:
        author = "valtersit.com"
        description = "Detects stored XSS payload patterns targeting Adobe Experience Manager form fields (CVE-2026-106629)"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-106629"
        date = "2026-01-01"
        severity = "critical"

    strings:
        $xss1 = "<script" nocase
        $xss2 = "</script>" nocase
        $xss3 = "javascript:" nocase
        $xss4 = "onerror=" nocase
        $xss5 = "onload=" nocase
        $xss6 = "onmouseover=" nocase
        $xss7 = "document.cookie" nocase
        $xss8 = "<img" nocase
        $xss9 = "<svg" nocase

    condition:
        (2 of ($xss*))
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-106629 Adobe Experience Manager Stored XSS Injection Attempt"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/content/"; http.request_body; content:"<script"; nocase; http.request_body; content:"</script>"; nocase; classtype:web-application-attack; reference:cve,2026-106629; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-106629; sid:2026106629; rev:1;)

Elastic Detection

process where event.type == "start" and
  process.name in ("java", "node") and
  process.command_line : "*content*" and
  process.command_line : ("*<script*" or "*onerror=*" or "*javascript:*")

Note: AEM is server-side; where full request logging is available, prefer EQL against HTTP access events containing stored-payload indicators rather than process events, as the marker for actual exploitation is a stored payload surfacing in a later GET response.

Splunk SPL Query

index=web sourcetype=access_combined
| eval payload=coalesce(uri_query, request_body)
| where match(payload, "(?i)(<script|%3Cscript|javascript:|onerror=|onload=|onmouseover=)")
| stats count min(_time) as first_seen max(_time) as last_seen by src_ip, uri_path, method
| where count > 0
| sort - count

Wazuh OSSEC Rule

<group name="web,appsec,cve-2026-106629,">
  <rule id="2026106629" level="10">
    <decoded_as>web-accesslog</decoded_as>
    <description>CVE-2026-106629: Possible stored XSS payload submitted to Adobe Experience Manager form</description>
    <regex type="pcre2">(?i)(POST|PUT).*(<script|%3Cscript|javascript:|onerror=|onload=|onmouseover=)</regex>
    <mitre>
      <id>T1059.007</id>
    </mitre>
    <group>web_attack,xss,cve_2026_106629,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 — UNPATCHED. No patch evidence from any tracked source; no vendor advisory, fixed version, or workaround is available in the provided data.

1. Immediate mitigations

   • Deploy a Web Application Firewall (WAF) with XSS rule sets and virtual patching focused on AEM form submission and content-rendering endpoints.
   • Enforce strict Content Security Policy (CSP) headers (nonce- or hash-based, no unsafe-inline) to reduce script execution even if a payload is stored.
   • Restrict and monitor who can submit content into form fields; apply principle-of-least-privilege to AEM author and publish roles.
   • Sanitize or disable any forms that echo stored user input until an official fix is applied.
   • Monitor server logs for stored script payloads and alert on anomalous rendering of stored content.

2. Patch / upgrade steps

   • No patch is currently identified. Subscribe to Adobe Security Bulletins (helpx.adobe.com/security.html) and Adobe APSB notices for the applicable AEM release. Apply the fixed cumulative/Service Pack release for your AEM version as soon as it is published.
   • Where AEM is deployed via a managed service or cloud offering, track the vendor's maintenance releases.

3. Long-term hardening

   • Adopt consistent context-aware output encoding and input validation across all server-rendered and form-backed AEM components.
   • Add automated web application scanning with an XSS-focused test suite in CI.
   • Maintain an asset inventory of all internet-facing AEM instances and reduce their exposure.
   • Increase monitoring and logging retention for CMS content modifications, and review admin/session activity regularly.
   • Track CVE-2026-106629 in vulnerability management tooling and reassess severity once EPSS or vendor data becomes available.

References

• NVD — CVE-2026-106629: https://nvd.nist.gov/vuln/detail/CVE-2026-106629
• CWE-79 — Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'): https://cwe.mitre.org/data/definitions/79.html
• Adobe Security Bulletins (Adobe Experience Manager advisories): https://helpx.adobe.com/security.html
• MITRE ATT&CK — T1059.007, Command and Scripting Interpreter: JavaScript: https://attack.mitre.org/techniques/T1059/007/
• FIRST EPSS (score not yet available for this CVE at time of writing): https://api.first.org/data/v1/epss

No known threat actor campaign or exploit-in-the-wild evidence has been identified for CVE-2026-106629. The CVE is not listed in CISA KEV, and no public PoC, exploit code, or Nuclei template was available at the time of this report.