Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate with valid credentials
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DeliveryCreate or modify email template with XSS payload
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ExploitEmail is logged to Event Log
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ExecutionVictim views mail preview in Event Log
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PersistMalicious JavaScript executes in victim's browser
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ImpactAttacker steals session or performs unauthorized action
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | The CVSS v4.0 score of 5.1 reflects a low-to-moderate vulnerability: network-accessible, low attack complexity, and no special privileges required to trigger user interaction-but critically, it requires prior authentication (PR:L) and user interaction (UI:P). The attack vector is non-adjacent network (AV:N), making it remotely exploitable. Impact is limited to low confidentiality and integrity loss; no availability or system scope changes. EPSS score and KEV status are not provided, so exploitation likelihood must be inferred from the data: this is a stored XSS requiring both authenticated access and social engineering (viewing a malicious log entry), which typically results in moderate real-world risk among multi-user systems but lower urgency than unauthenticated remote code execution. The workaround recommendations (restricting mail template editing and Event Log access) indicate the vendor recognizes this as a privileged-user attack surface, reducing enterprise risk for organizations with strong access controls. The patched versions (3.7.14 and 4.1.10) are available, making this a routine remediation priority rather than a critical emergency. |
| Exploit ScenarioDerived | An authenticated attacker with mail template editing privileges crafts a malicious HTML email template containing embedded JavaScript (e.g., stealing session cookies or CSRF tokens). When an administrator or other authorized user views the logged mail message in the Event Log, the iframe renders the HTML without sandbox restrictions, and the JavaScript executes in the viewer's browser context with the same privileges, potentially capturing credentials or performing actions on behalf of the victim. |
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Alert meAnalysisAIv1 – Apr 14, 2026
Stored cross-site scripting (XSS) in October CMS versions prior to 3.7.14 and 4.1.10 allows authenticated users with Event Log viewing permissions to execute arbitrary JavaScript in other users' browsers via malicious HTML content in the mail preview iframe. The vulnerability stems from improper iframe sandboxing when rendering logged email messages, affecting confidentiality and integrity with a CVSS score of 5.1. No public exploit code has been identified at the time of analysis.
RemediationAI
Upgrade October CMS to version 3.7.14 or later for the 3.x branch, or to version 4.1.10 or later for the 4.x branch. Vendor-released patches are available for both affected release lines. If immediate patching is not feasible, implement interim controls by restricting mail template editing permissions to fully trusted administrators only and limiting Event Log viewing permissions to authorized personnel. These workarounds reduce the attack surface by limiting who can inject malicious content and who can trigger the XSS payload. Detailed guidance is available in the official advisory at https://github.com/octobercms/october/security/advisories/GHSA-j4j5-9x6g-rgxc.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 2 packages in composer, euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
October CMS is a Laravel-based content management system that logs email communications for administrative review. The Event Log mail preview feature renders HTML email content within an iframe element without proper Content Security Policy (CSP) sandboxing or attribute restrictions. The underlying flaw is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), where user-controlled email template content is rendered without sanitization. An authenticated attacker can inject malicious JavaScript into email templates or logged messages, which executes in the context of any administrator or user viewing that log entry, bypassing same-origin restrictions due to missing sandbox attributes or Content-Security-Policy headers on the iframe.
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Primary rating from Vendor (GitHub_M) · only source for this CVE.
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
3DescriptionCVE.org
October is a Content Management System (CMS) and web platform. Versions prior to 3.7.14 and 4.1.10 contain a stored cross-site scripting (XSS) vulnerability in the Event Log mail preview feature. When viewing logged mail messages, HTML content was rendered in an iframe without proper sandboxing, allowing JavaScript execution in the viewer's browser context. This issue has been fixed in versions 3.7.14 and 4.1.10. If users are unable to update immediately, workarounds include restricting mail template editing permissions to fully trusted administrators only and restricting Event Log viewing permissions to minimize exposure.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.
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EUVD-2026-22660
GHSA-j4j5-9x6g-rgxc
NVD
CVE.org
EPSS
Vulnrichment
Exploit-DB