CVE-2025-9039: We identified an issue in the Amazon ECS agent where, under certain conditions, an introspection server could be accessed off-host by another instance if the in

We identified an issue in the Amazon ECS agent where, under certain conditions, an introspection server could be accessed off-host by another instance if the in

We identified an issue in the Amazon ECS agent where, under certain conditions, an introspection server could be accessed off-host by another instance if the instances are in the same security group or if their security groups allow incoming connections that include the port where the server is hosted. This issue does not affect instances where the option to allow off-host access to the introspection server is set to 'false'. This issue has been addressed in ECS agent version 1.97.1. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes. If customers cannot update to the latest AMI, they can modify the Amazon EC2 security groups to restrict incoming access to the introspection server port (51678).

Description from the National Vulnerability Database, published by ff89ba41-3aa1-4d27-914a-91399e9639e5

What it means for a small business

If your business uses ECS, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.28%, higher than 20% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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