high CVSS 7.5

CVE-2026-44432·Python vulnerability

urllib3 is an HTTP client library for Python. From 2.6.0 to before 2.7.0, urllib3 could decompress the whole response instead of the requested portion (1) during the second HTTPResponse.read(amt=N) call when the response was decompressed using the official Brotli library or (2) when HTTPResponse.drain_conn() was called after the response had been read and decompressed partially (compression algorithm did not matter here). These issues could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This could result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data) on the client side. This vulnerability is fixed in 2.7.0.

Severity
high
Software
Python
Fixed in
2.7.0
Published
2026-05-13

Affected versions

From: 2.6.0

Until: 2.7.0

Fixed in: 2.7.0

How to fix this CVE

Upgrade urllib3 to version 2.7.0 or later to prevent decompression-related denial-of-service attacks. This vulnerability allows attackers to trigger excessive CPU and memory consumption by forcing the library to fully decompress highly compressed HTTP responses. Update your Python environment immediately if you are running urllib3 versions 2.6.0 through 2.6.x.

sudo dnf update python3-urllib3

Defensia detects this vulnerability

How to check if you are affected

  1. Check the installed urllib3 version: python3 -c "import urllib3; print(urllib3.__version__)"
  2. Verify if urllib3 is in use: pip3 show urllib3 | grep Version
  3. Search application logs for decompression errors: grep -r "decompress\|Brotli" /var/log/
  4. Confirm the patch by re-running: python3 -c "import urllib3; print(urllib3.__version__)" (should show 2.7.0 or higher)

FAQ

What is CVE-2026-44432?

CVE-2026-44432 is a denial-of-service vulnerability in urllib3 where decompression of HTTP responses can be triggered to consume all available system memory and CPU resources. The flaw occurs during partial reads or when drain operations follow decompression, particularly with Brotli-compressed content.

Is CVE-2026-44432 being actively exploited?

No, there are no reports of active exploitation or publicly available exploits for this vulnerability at this time, though it should still be patched as a precaution.

What versions of Python are affected by CVE-2026-44432?

The vulnerability affects urllib3 versions 2.6.0 through 2.6.x. Python 3.x installations that depend on vulnerable urllib3 packages are at risk.

How do I check if my server is vulnerable to CVE-2026-44432?

Run: python3 -c "import urllib3; v = urllib3.__version__.split('.'); print('Vulnerable' if int(v[0])==2 and int(v[1])==6 else 'Safe')"

Does Defensia detect CVE-2026-44432?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If urllib3 or Python is installed on a monitored server, CVE-2026-44432 will appear in your dashboard with remediation steps.

Related Python CVEs

CVE-2026-28505CVSS 10Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Prior to version 2.17.0, the str_eval() function in notification_handler.py implements a sandboxed eval() for notification text templates. The sandbox attempts to restrict callable names by inspecting code.co_names of the compiled code object. However, co_names only contains names from the outer code object. When a lambda expression is used, it creates a nested code object whose attribute accesses are stored in code.co_consts, NOT in code.co_names. The sandbox never inspects nested code objects. This issue has been patched in version 2.17.0.
CVE-2026-25632CVSS 10EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water distribution networks. Prior to 0.16.1, EPyT-Flow’s REST API parses attacker-controlled JSON request bodies using a custom deserializer (my_load_from_json) that supports a type field. When type is present, the deserializer dynamically imports an attacker-specified module/class and instantiates it with attacker-supplied arguments. This allows invoking dangerous classes such as subprocess.Popen, which can lead to OS command execution during JSON parsing. This also affects the loading of JSON files. This vulnerability is fixed in 0.16.1.
CVE-2026-34938CVSS 10PraisonAI is a multi-agent teams system. Prior to version 1.5.90, execute_code() in praisonai-agents runs attacker-controlled Python inside a three-layer sandbox that can be fully bypassed by passing a str subclass with an overridden startswith() method to the _safe_getattr wrapper, achieving arbitrary OS command execution on the host. This issue has been patched in version 1.5.90.
CVE-2026-33054CVSS 10Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation. This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.
CVE-2026-25115CVSS 9.9n8n is an open source workflow automation platform. Prior to version 2.4.8, a vulnerability in the Python Code node allows authenticated users to break out of the Python sandbox environment and execute code outside the intended security boundary. This issue has been patched in version 2.4.8.

References

Track CVEs across your fleet automatically

Defensia scans your Linux servers and tells you exactly which ones are running vulnerable versions — including CVE-2026-44432. Free for 1 server.

Get started free