CVE-2025-63235
CVE-2025-63235 is a security vulnerability. O3 Security confirms whether CVE-2025-63235 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
In sol commit 373d848 (2024-12-12), the broker does not fully release resources when handling malformed or duplicate CONNECT packets. When clients send invalid CONNECT packets - either…
Description
In sol commit 373d848 (2024-12-12), the broker does not fully release resources when handling malformed or duplicate CONNECT packets. When clients send invalid CONNECT packets - either due to repeated attempts or failed authentication - the server may silently drop the connection or send a CONNACK but fail to close the session or deallocate internal resources. This behavior allows an attacker to create numerous half-open connections that consume memory and file descriptors indefinitely, potentially triggering the Linux OOM killer and causing a denial of service.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2025-63235 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-63235 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2025-63235. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-63235 in your dependencies?
O3 detects CVE-2025-63235 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.