python-socketio — security advisory
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.
- Products
- python-socketio
- Affected versions
- 4.4.0-1, 4.4.0-2, 5.0.3-2, 5.13.0-1, 5.16.0-1, 5.7.2-2
- Fixed versions
- Not specified
- CVEs
- CVE-2026-48804
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:21 UTC · Revision 1
Source evidence
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.
osv:UBUNTU-CVE-2026-48804
python-socketio
Fixed versions: Not specified
python-socketio
Fixed versions: Not specified
python-socketio
Fixed versions: Not specified
python-socketio
Fixed versions: Not specified
python-socketio
Fixed versions: Not specified
Complete source record
{
"id": "d3f9934652fb1b75b047ae303eafe5b85debc141af7afd04c8aa21c6acf95bfa",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-48804",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-48804",
"summary": "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.",
"evidence": "osv:UBUNTU-CVE-2026-48804",
"products": [
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"evidence": "/affected/0/package/name"
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"aliases": [
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"metrics": [
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"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
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"affected": [
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"modified": "2026-10-17T12:58:31.852468150Z",
"provider": "osv",
"upstream": [
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],
"references": [
"https://ubuntu.com/security/CVE-2026-48804",
"https://www.cve.org/CVERecord?id=CVE-2026-48804",
"https://github.com/miguelgrinberg/python-socketio/commit/4bec3ef87bcfd6ab5b94cd3ac09d873283a6960e",
"https://github.com/miguelgrinberg/python-socketio/security/advisories/GHSA-5w7q-77mv-v69f"
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},
"related_cves": [
{
"value": "CVE-2026-48804",
"evidence": "/upstream"
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"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 358698,
"published_at": "2026-08-11T20:17:00+00:00"
}