CVE-2026-2469 is a vulnerability identified in the directorytree/imapengine PHP package, specifically affecting versions prior to 1.22.3. The flaw exists in the id() function of ImapConnection.php, where user input is improperly escaped before being incorporated into IMAP ID commands. This improper neutralization of special elements, such as quote characters (") and carriage return/line feed sequences (\r\n), enables injection attacks. An attacker can exploit this by crafting malicious input that manipulates the IMAP command stream, allowing execution of arbitrary IMAP commands on the victim's mailbox. Potential impacts include unauthorized reading or deletion of emails, forced termination of the victim's IMAP session, and broader mailbox manipulation. The vulnerability is exploitable remotely over the network without requiring user interaction or elevated privileges, increasing its risk profile. The CVSS 4.0 vector reflects network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and high impact on availability (VA:H), with limited confidentiality and integrity impact. Although no exploits are currently known in the wild, the vulnerability's nature and ease of exploitation make it a significant threat to any system using vulnerable versions of directorytree/imapengine for IMAP communications. The lack of proper input sanitization in a critical email handling component highlights the importance of secure coding practices in email client libraries. The vulnerability was published on February 14, 2026, and users are advised to upgrade to version 1.22.3 or later where the issue is fixed.

For European organizations, this vulnerability poses a serious risk to the confidentiality, integrity, and availability of email communications. Email is a critical business tool, and unauthorized access or manipulation of mailboxes can lead to data breaches, loss of sensitive information, disruption of business operations, and reputational damage. Attackers exploiting this flaw could read confidential emails, delete important messages, or disrupt user sessions, potentially causing denial of service. Organizations relying on directorytree/imapengine in their mail infrastructure or custom email clients are particularly vulnerable. The ability to execute arbitrary IMAP commands remotely without authentication or user interaction increases the attack surface and likelihood of exploitation. This can affect sectors such as finance, government, healthcare, and enterprises with high email dependency. Additionally, compromised mailboxes can be leveraged for further phishing or lateral movement within networks. The absence of known exploits currently provides a window for proactive mitigation, but the high CVSS score indicates that the threat should be treated with urgency.

1. Immediately upgrade all instances of directorytree/imapengine to version 1.22.3 or later, where the vulnerability is patched. 2. Implement strict input validation and output encoding on all user inputs that interact with IMAP commands, especially those involving the id() function or similar interfaces. 3. Employ network-level monitoring and anomaly detection to identify unusual IMAP command sequences or session terminations indicative of exploitation attempts. 4. Restrict access to IMAP services using network segmentation, firewalls, and access control lists to limit exposure to trusted users and systems only. 5. Conduct regular security audits and code reviews of email handling components to detect similar injection flaws. 6. Educate developers and administrators on secure coding practices related to command injection and input sanitization. 7. Maintain up-to-date backups of email data to enable recovery in case of data deletion or corruption. 8. Monitor vendor advisories and threat intelligence feeds for any emerging exploits targeting this vulnerability.