Srimax Output Messenger: file access flaw under attack

What is affected

Srimax Output Messenger is mostly run by companies, schools and public bodies, not on home computers. You are unlikely to have it yourself, but organisations that hold your data may. Breaches that start with flaws like this one are how personal data ends up leaked.

Srimax Output Messenger contains a directory traversal vulnerability that allows an attacker to access sensitive files outside the intended directory, potentially leading to configuration leakage or arbitrary file access.

What an attacker can do

This is a file access flaw. It lets an attacker read or write files they should never reach, such as configuration files that hold passwords, or upload a malicious file that the system then runs.

How it is reached

Over the internet or network

Access the attacker needs

A basic user account

Does the victim have to do something?

No, works without the victim doing anything

What to do

1. At home: nothing to install. Keep your own devices updated and use a different password for every service, so that a breach at one organisation does not open your other accounts.
2. If you administer Srimax Output Messenger at work: apply the vendor's fix or mitigation now and review logs for signs of compromise, because the flaw was being exploited before it was listed.
3. If the product is past its support date and no fix exists, take it off the internet or retire it.

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor advisories and fixes

• outputmessenger.comwww.outputmessenger.com/cve-2025-27920/

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on May 19, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by June 9, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 1.9% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 79% of all scored vulnerabilities.

Its CVSS severity score is 8.8 out of 10 (high), as recorded in the US National Vulnerability Database.

Technical description

Output Messenger before 2.0.63 was vulnerable to a directory traversal attack through improper file path handling. By using ../ sequences in parameters, attackers could access sensitive files outside the intended directory, potentially leading to configuration leakage or arbitrary file access.