CVE-2026-30458: FuelCMS Information Disclosure Vulnerability

CVE-2026-30458 Overview

A vulnerability has been identified in Daylight Studio FuelCMS version 1.5.2 that allows attackers to exfiltrate users' password reset tokens via a mail splitting attack. This vulnerability enables threat actors to manipulate the email functionality within the CMS to intercept sensitive password reset tokens, potentially leading to account takeover scenarios.

Critical Impact

Attackers can exploit the mail splitting vulnerability to intercept password reset tokens, enabling unauthorized access to user accounts and potential full account takeover.

Affected Products

• Daylight Studio FuelCMS v1.5.2

Discovery Timeline

• 2026-03-26 - CVE CVE-2026-30458 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2026-30458

Vulnerability Analysis

This vulnerability involves a mail splitting attack (also known as email header injection) in Daylight Studio FuelCMS v1.5.2. Mail splitting attacks exploit improper validation of user-supplied input in email-related functionality, allowing attackers to inject additional email headers or manipulate existing ones.

In the context of FuelCMS, the vulnerability specifically targets the password reset functionality. When a user requests a password reset, the application generates a token and sends it via email. By exploiting the mail splitting vulnerability, an attacker can manipulate the email headers to add additional recipients (such as their own email address) to receive a copy of the password reset token.

The attack enables account takeover by allowing malicious actors to intercept legitimate password reset tokens intended for other users. Once the attacker obtains the token, they can complete the password reset process and gain unauthorized access to the victim's account.

Root Cause

The root cause of this vulnerability is improper input validation and sanitization in the email handling functionality of FuelCMS v1.5.2. The application fails to properly sanitize user-controlled input before incorporating it into email headers, allowing attackers to inject CRLF (Carriage Return Line Feed) sequences that create additional email headers.

When email header values are constructed using unsanitized user input, attackers can terminate the current header and inject new headers such as CC:, BCC:, or even modify the To: field. This allows the password reset email containing the sensitive token to be sent to attacker-controlled email addresses.

Attack Vector

The attack is executed remotely through manipulation of the password reset request. An attacker can craft a malicious request that injects additional email headers into the password reset email functionality. The typical attack flow involves:

1. The attacker initiates a password reset request for a target user account
2. Within the request, the attacker injects CRLF sequences followed by additional email headers (e.g., BCC: attacker@malicious.com)
3. The vulnerable application processes the request without proper sanitization
4. The password reset email is sent to both the legitimate user and the attacker
5. The attacker receives the password reset token and can use it to take over the account

The vulnerability can be exploited without authentication, as password reset functionality is typically accessible to unauthenticated users. For more technical details, refer to the Pentest Tools security report.

Detection Methods for CVE-2026-30458

Indicators of Compromise

• Unusual email headers in outgoing password reset emails, particularly unexpected CC: or BCC: recipients
• Log entries showing password reset requests containing CRLF characters (%0d%0a, \r\n) in input fields
• Multiple password reset requests for the same account from different IP addresses in short time periods
• Successful account logins following password resets where the legitimate user did not initiate the reset

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing CRLF injection patterns in email-related parameters
• Monitor email server logs for anomalies in outgoing password reset emails, including unexpected recipient additions
• Deploy input validation alerts for any user-supplied data containing newline characters being processed by email functions
• Review application logs for patterns indicative of mail splitting attempts in password reset workflows

Monitoring Recommendations

• Enable detailed logging on all password reset functionality and email transmission events
• Configure alerts for password reset requests that originate from suspicious or known-malicious IP addresses
• Monitor for multiple failed or successful password resets targeting the same user account within short time windows
• Implement email security monitoring to detect unauthorized modifications to email headers

How to Mitigate CVE-2026-30458

Immediate Actions Required

• Upgrade FuelCMS to the latest available version if a patch has been released by Daylight Studio
• Review and audit all password reset functionality for proper input validation and sanitization
• Implement strict input validation to reject any email-related input containing CRLF characters
• Consider temporarily disabling the password reset feature if exploitation is suspected

Patch Information

Users of FuelCMS v1.5.2 should monitor the official GitHub FUEL-CMS Repository for security updates and patches addressing this vulnerability. Review the Daylight Studio website and FuelCMS official site for any security advisories.

Workarounds

• Implement server-side input validation to strip or reject any input containing carriage return (\r) or line feed (\n) characters before processing email functions
• Deploy a Web Application Firewall (WAF) with rules to block requests containing email header injection patterns
• Use email libraries or frameworks that automatically sanitize header inputs and prevent header injection attacks
• Restrict password reset functionality to known, verified email addresses and implement rate limiting to slow down potential exploitation attempts
• Consider implementing additional verification steps in the password reset flow, such as CAPTCHA or multi-factor verification