A high‑severity vulnerability in the Laravel framework can let attackers manipulate outbound email processing, potentially causing unauthorized delivery, data exposure, or abuse of mail relays.
Tracked as CVE-2026-48019 and documented in GitHub advisory GHSA-5vg9-5847-vvmq, the flaw arises from improper neutralization of CRLF (Carriage Return Line Feed) sequences in Laravel’s default email validation.
Laravel CRLF Injection Vulnerability
Laravel’s email validation once allowed user-supplied addresses containing control sequences (\r\n) to pass through to underlying mail components specifically Symfony Mailer and Symfony Mime without sufficient sanitization.
When CRLF sequences are retained, an attacker can inject new header lines into structured email data, a class of issue known as CRLF injection (CWE-93).
If an application accepts user input for email fields (for example, registration, contact forms, or administrative inputs) and relies on the framework’s default validation, an attacker can submit an address: victim@example.com\r\nBcc: attacker@evil.com
When processed without neutralizing the CRLF, the mail stack may treat the injected text as an additional header. That can cause the application to send copies to unintended recipients, alter headers, or otherwise change how the message is routed or interpreted.
Exploitability depends on the application’s email workflows and mail server configuration. Because the flaw can be triggered by unauthenticated, user-controlled fields, publicly accessible Laravel applications are at higher risk. Possible outcomes include:
- Unauthorized forwarding of sensitive emails (password reset or verification messages).
- Message content or header manipulation, leading to data leakage or phishing amplification.
- Abuse of the application’s mail infrastructure to relay spam or malicious mail.
The vulnerability is rated high and given the CVSS vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L. This reflects significant confidentiality and integrity impact, noting a higher attack complexity but no required privileges or user interaction.
Mitigation
The issue was responsibly disclosed by security researcher OmarXtream. Laravel maintainers have fixed the issue by tightening email input validation and ensuring CRLF sequences are neutralized before reaching the mail transport layer. Immediate actions for organizations:
- Upgrade to patched framework versions: Laravel >= 13.10.0 or Laravel >= 12.60.0.
- Validate inputs strictly: explicitly reject control characters, especially \r and \n, from email fields.
- Sanitize before handing data to mail libraries (defensive coding even when using framework validation).
- Enforce mail server protections to detect or block anomalous headers and suspicious outbound recipients.
- Monitor outbound mail logs for unusual destinations, spikes in Bcc/Cc entries, or repeated header anomalies.
Affected and patched versions
- Affected: Laravel <= 13.9.0, Laravel < 12.60.0
- Patched: Laravel >= 13.10.0, Laravel >= 12.60.0
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