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PythonApplication

CVE-2022-42919

HIGH · 7.8 CVSS v3.1 Published 2022-11-07
Fix available
A fix is available. Upgrade to 3.9.16 / 3.10.9 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Python 3.9.x before 3.9.16 and 3.10.x before 3.10.9 on Linux allows local privilege escalation in a non-default configuration. The Python multiprocessing library, when used with the forkserver start method on Linux, allows pickles to be deserialized from any user in the same machine local network namespace, which in many system configurations means any user on the same machine. Pickles can execute arbitrary code. Thus, this allows for local user privilege escalation to the user that any forkserver process is running as. Setting multiprocessing.util.abstract_sockets_supported to False is a workaround. The forkserver start method for multiprocessing is not the default start method. This issue is Linux specific because only Linux supports abstract namespace sockets. CPython before 3.9 does not make use of Linux abstract namespace sockets by default. Support for users manually specifying an abstract namespace socket was added as a bugfix in 3.7.8 and 3.8.3, but users would need to make specific uncommon API calls in order to do that in CPython before 3.9.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Python's multiprocessing library with forkserver start method on Linux uses abstract namespace sockets that allow pickles to be deserialized from any user in the same local network namespace, enabling arbitrary code execution and local privilege escalation to the forkserver process user.

MitigationUpgrade Python to 3.9.16+/3.10.9+ or set multiprocessing.util.abstract_sockets_supported = False before using the forkserver start method.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
PythonApplication
Affected:>= 3.7.3, <= 3.7.15>= 3.8.3, <= 3.8.15>= 3.9.0, < 3.9.16>= 3.10.0, < 3.10.9
FedoraOperating system
Affected:= 35= 36= 37

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Python version
    Run 'python3 --version' or 'python --version' to get the installed Python version
    Affected if Version is 3.7.3-3.7.15, 3.8.3-3.8.15, 3.9.0-3.9.15, or 3.10.0-3.10.8 (the affected ranges)
  2. Confirm Linux operating system
    Run 'uname -s' or check that the OS is Linux-based. Abstract namespace sockets are a Linux-specific feature.
    Affected if Running on Linux (the vulnerability only applies to Linux systems using abstract namespace sockets)
  3. Identify multiprocessing start method
    Search code for 'multiprocessing.set_start_method('forkserver')' or 'multiprocessing.start_method = 'forkserver''. Also check if the environment variable 'PYTHONSTARTUP' or scripts invoke forkserver implicitly.
    Affected if The application uses 'forkserver' as the multiprocessing start method
  4. Verify mitigation not applied
    Check if 'multiprocessing.util.abstract_sockets_supported' has been set to False before any forkserver usage. Run: python3 -c 'import multiprocessing.util; print(getattr(multiprocessing.util, "abstract_sockets_supported", "not set"))'
    Affected if abstract_sockets_supported is not set to False (default is True, meaning vulnerable)

You are affected if you run Python 3.7.3-3.10.8 on Linux and use the forkserver multiprocessing start method without having set abstract_sockets_supported to False.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 3.9.16 / 3.10.9 or later
Fixed in 3.9.163.10.9
Interim mitigation

Upgrade Python to 3.9.16+/3.10.9+ or set multiprocessing.util.abstract_sockets_supported = False before using the forkserver start method.

Recommended fix High confidence

Python 3.9.16 or later, or Python 3.10.9 or later (depending on major version in use)

  1. Check current Python version: python3 --version
  2. For Fedora systems (35, 36, 37), update Python via: sudo dnf update python3
  3. For Debian/Ubuntu, upgrade to Python 3.9.16+: sudo apt-get update && sudo apt-get install python3.9 (or python3.10)
  4. Verify the fixed version is installed: python3 --version (should show 3.9.16+, 3.10.9+, or later)
  5. Alternatively, as a configuration workaround (if upgrade is not immediately feasible), add this at application startup before using multiprocessing: import multiprocessing.util; multiprocessing.util.abstract_sockets_supported = False
Caveat Minimal - these are security patch releases with no expected breaking changes to existing code

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Python Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-42919 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data