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xx_ns | 4 months ago

I pentest network devices (amongst other things) for a living, and the way these usually work is that they have dnsmasq running in the background and to accept user config values, templating is used to generate dnsmasq-specific configuration files which are then fed into dnsmasq. I cannot overstate how common this method is.

Some devices do this more securely than others. If you're able to inject newlines, it's highly likely that you can already achieve command execution by injecting directives. I wrote a bit about this technique here: https://blog.nns.ee/2025/07/24/dnsmasq-injection-trick/ (sorry for the self-plug). I think it's up to the device vendor to do this securely and not a concern for dnsmasq.

However, in this case, I feel like the concern is elsewhere and not the sole responsibility of the device vendors. Even if the vendor does templating securely, the vulnerable config options could still trigger the bug in dnsmasq itself and give some advantage to the attacker. Assuming the vulnerabilities themselves are legit, I'm finding it difficult to classify these issues as "bogus".

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ValdikSS|4 months ago

Kubernetes do that as well