TeleMessage TM SGNL: memory corruption flaw under attack

What is affected

TeleMessage TM SGNL 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.

TeleMessage TM SGNL contains an initialization of a resource with an insecure default vulnerability. This vulnerability relies on how the Spring Boot Actuator is configured with an exposed heap dump endpoint at a /heapdump URI.

What an attacker can do

This is a memory corruption flaw. It lets an attacker corrupt the program's memory by feeding it specially crafted content: a web page, a file or a network message. The result ranges from a crash to the attacker running their own code.

How it is reached

Over the internet or network

Access the attacker needs

No account needed

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 TeleMessage TM SGNL 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.

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on July 1, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by July 22, 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 11% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 96% of all scored vulnerabilities.

Its CVSS severity score is 5.3 out of 10 (medium), as recorded in the US National Vulnerability Database.

Technical description

The TeleMessage service through 2025-05-05 configures Spring Boot Actuator with an exposed heap dump endpoint at a /heapdump URI, as exploited in the wild in May 2025.