Socket.IO Memory Exhaustion Vulnerability: Early Warning
An early warning has been issued regarding a potential vulnerability in Socket.IO that could lead to memory exhaustion. Users of affected versions are advised to upgrade.
What happened
Reportedly, a specially crafted Socket.IO packet can cause the server to wait for a large number of binary attachments and buffer them, potentially leading to memory exhaustion. This issue is under investigation and has been assigned a high severity rating. Affected versions include socket.io (npm) >=4.0.0,<4.2.7,>=3.4.0,<3.4.5,<3.3.6 and socket.io-client (npm) >=4.0.0,<4.2.7. It is recommended to upgrade to socket.io@4.2.7 or socket.io-client@4.2.7 to mitigate the risk. For more details, consult the primary sources: [GHSA-2m8v-j782-fhvr](https://github.com/socketio/socket.io/security/advisories/GHSA-2m8v-j782-fhvr) and [CVE-2026-53984](https://nvd.nist.gov/vuln/detail/CVE-2026-53984).
The vulnerability appears to exploit a zero-attachment scenario, causing the server to buffer an excessive amount of data, which can exhaust available memory resources. This could potentially lead to server instability or denial of service. The CVSS score for this vulnerability is 9.1, indicating a critical level of severity. Users should assess their exposure by checking their Socket.IO versions against the affected ranges and applying the recommended upgrades as soon as possible.
How 0Day mitigates this
socket.io is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.