high CVSS 7.5

CVE-2026-32274·Python vulnerability

Black is the uncompromising Python code formatter. Starting in version 24.3.0 and prior to version 26.3.1, Black writes a cache file, the name of which is computed from various formatting options. The value of the --python-cell-magics option was placed in the filename without sanitization, which allowed an attacker who controls the value of this argument to write cache files to arbitrary file system locations. Fixed in Black 26.3.1.

Severity
high
Software
Python
Fixed in
26.3.1
Published
2026-03-12

Affected versions

Until: 26.3.1

Fixed in: 26.3.1

How to fix this CVE

Update Black to version 26.3.1 or later to remediate a path traversal vulnerability in the cache file naming mechanism. The --python-cell-magics option was not properly sanitized, allowing attackers to write cache files to arbitrary filesystem locations. Ensure all Python installations using Black for code formatting are patched immediately.

sudo dnf update python3-black

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check the installed Black version by running: python3 -m pip show black | grep Version
  2. Step 2: Verify if Black is actively used in your CI/CD pipelines or development environments by searching: grep -r 'black' /etc/systemd/system/ ~/.bashrc ~/.bash_profile
  3. Step 3: Search system logs for suspicious cache file creation patterns: grep -r 'cache' /var/log/apt/history.log /var/log/dnf.log | grep -i black
  4. Step 4: Confirm the fix by re-running: python3 -m pip show black | grep Version and verify it reports 26.3.1 or higher

FAQ

What is CVE-2026-32274?

CVE-2026-32274 is a path traversal vulnerability in Black (Python code formatter) versions 24.3.0 through 26.3.0 where unsanitized command-line arguments in the --python-cell-magics option could allow arbitrary cache file writes to the filesystem.

Is CVE-2026-32274 being actively exploited?

No, this vulnerability is not currently listed in CISA's Known Exploited Vulnerabilities catalog and no public exploits are available.

What versions of Python are affected by CVE-2026-32274?

Black versions from 24.3.0 up to and including 26.3.0 are vulnerable; Python itself is not directly affected but Black installations on Python 3.x systems require the update.

How do I check if my server is vulnerable to CVE-2026-32274?

Run: python3 -m pip show black | grep Version and verify the version is below 26.3.1; also check if --python-cell-magics is used in your development or CI workflows.

Does Defensia detect CVE-2026-32274?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Black is installed on a monitored server, CVE-2026-32274 will appear in your dashboard with remediation steps.

Related Python CVEs

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-2026-34938CVSS 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-2026-25632CVSS 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-2026-28505CVSS 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-2026-25115CVSS 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-2026-32274. Free for 1 server.

Get started free