SB2025051322 - Multiple vulnerabilities in Output Messenger

Description

This security bulletin contains information about 2 vulnerabilities.

1) Path traversal (CVE-ID: CVE-2025-27920)

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber

The vulnerability allows a remote user to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences. A remote authenticated user can upload malicious files to an arbitrary location on the system and execute them, leading to full system compromise.

Note, the vulnerability is being actively exploited in the wild.

2) Cross-site scripting (CVE-ID: CVE-2025-27921)

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Remediation

Install update from vendor's website.

References

• https://www.outputmessenger.com/cve-2025-27920/
• https://www.microsoft.com/en-us/security/blog/2025/05/12/marbled-dust-leverages-zero-day-in-output-messenger-for-regional-espionage/
• https://www.outputmessenger.com/cve-2025-27921/