Vulnerability · Published Aug 11, 2026 · Assigned by GitHub_M
CVE-2026-48804python-socketio: Binary attachment accumulation can cause denial of service
High 7.5
In plain English
A high-severity resource allocation without limits in python-socketio from miguelgrinberg. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
python-socketio is a Python implementation of the Socket.IO realtime client and server. The python-socketio server stores binary `EVENT` and `ACK` messages in memory while it waits to receive their binary attachments. Once all the attachments are received, these messages are then processed. Prior to version 5.16.4, an attacker can submit a binary message and intentionally omit sending one or more of its attachments to cause the message along with the partial list of received attachments to stay in memory for a long time. Version 5.16.4 takes the following measures to address this issue: Binary packets are only accepted from authenticated clients and, when a client disconnects, the server checks if there is a partial binary message being held for the client and deletes it.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-socketio | no fix listed | DEBIAN-CVE-2026-48804 |
| Debian:13 | python-socketio | no fix listed | DEBIAN-CVE-2026-48804 |
| Debian:14 | python-socketio | 5.17.0-1 | DEBIAN-CVE-2026-48804 |
| PyPI | python-socketio | 5.16.2 | GHSA-5w7q-77mv-v69f |
| PyPI | python-socketio | 5.16.2 | PYSEC-2026-3042 |
| Ubuntu:22.04:LTS | python-socketio | no fix listed | UBUNTU-CVE-2026-48804 |
| Ubuntu:24.04:LTS | python-socketio | no fix listed | UBUNTU-CVE-2026-48804 |
| Ubuntu:26.04:LTS | python-socketio | no fix listed | UBUNTU-CVE-2026-48804 |
| Ubuntu:26.10 | python-socketio | no fix listed | UBUNTU-CVE-2026-48804 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| miguelgrinberg | python-socketio | < 5.16.4 |
Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H