Vulnerability in python-engineio (CVE-2026-48809)
Summary
Vulnerability in python-engineio (CVE-2026-48809). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 4.13.2 or later.
Original description
The description as published by the source.
python-engineio is a Python implementation of the Engine.IO realtime client and server. Versions prior to 4.13.2 have two specific configurations of the python-engineio server in which the size of incoming messages is not checked before the messages are loaded into memory. An attacker can take advantage of these to cause unnecessary memory allocations in the python-engineio server. The two cases are POST requests, when using ASGI with the long polling transport and WebSocket messages, when using Aiohttp with the WebSocket transport. Version 4.13.2 addresses this issue. ASGI severs now only load the body of incoming requests into memory after the client is confirmed to be known and authenticated, and the payload size is below the maximum allowed size. Requests that do not comply with these requirements are discarded. Aiohttp servers configure the maximum payload size in the underlying WebSocket layer from Aiohttp, so that large messages are discarded by Aiohttp before they are delivered to python-engineio.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-48809 has been found in python-engineio.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade python-engineio to 4.13.2 or later.
If unsure, ask your IT team or search "python-engineio CVE-2026-48809" on the vendor's site.
CVE-2026-48809 (python-engineio) — CWE-770 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 4.13.2 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-770) exists in python-engineio.
Check the vendor advisory for the affected versions of python-engineio.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 4.13.2.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'python-engineio' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'python-engineio' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
python-engineioを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade python-engineio to 4.13.2ステージング環境で 4.13.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-48809 python-engineio
- Ubuntu UBUNTU-CVE-2026-48809 python-engineio
References
- advisory github.com
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- web github.com