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CVE-2022-42919: 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-def...

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.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This is a local privilege-escalation issue in certain Linux Python 3.9 and 3.10 deployments using multiprocessing forkserver. A lower-privileged user on the same host may be able to feed unsafe serialized data to a forkserver process and run code as that process's user. It is not a default configuration.

Executive priority

Treat as high priority for Linux multi-user or shared infrastructure using Python multiprocessing forkserver. It is lower urgency for single-user systems or applications that never use forkserver, but affected fleet visibility should be established quickly.

Technical view

CVE-2022-42919 is CWE-502 unsafe deserialization. Python multiprocessing forkserver on Linux used abstract namespace sockets, allowing pickle data from users in the same local network namespace. Python 3.9 before 3.9.16 and 3.10 before 3.10.9 are named as affected.

Likely exposure

Exposure is mainly Linux systems running affected Python versions where applications explicitly use multiprocessing forkserver. Typical risk is multi-user hosts, shared compute, CI/build systems, or services running forkserver under a more privileged account.

Exploitation context

The CVE is not listed as CISA KEV in the provided data, and the bundle gives no evidence of active exploitation. Attackers need local user access and a vulnerable forkserver reachable within the same local network namespace.

Researcher notes

The key condition is not just Python version; it is forkserver usage on Linux with abstract namespace sockets. CPython before 3.9 is described as not using these sockets by default, with uncommon manual API paths in some earlier releases.

Mitigation direction

  • Upgrade Python 3.9 to 3.9.16 or later.
  • Upgrade Python 3.10 to 3.10.9 or later.
  • Review vendor advisories for distribution-specific package versions.
  • Set multiprocessing.util.abstract_sockets_supported to False where immediate upgrade is not possible.
  • Avoid forkserver start method for higher-privilege processes until remediated.

Validation and detection

  • Inventory Linux hosts running Python 3.9.x or 3.10.x.
  • Identify applications using multiprocessing forkserver start method.
  • Check whether Python package versions include vendor backports.
  • Prioritize multi-user systems and privileged service accounts.
  • Confirm workaround or upgrade in staging before production rollout.
Prepared
Confidence
high
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-502: Code execution behavior lookup

Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
description · low confidence lookup

Privilege behavior lookup

The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2022-42919 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
15Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2022-42919Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

CWE-502

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-502 · source CWE mapping

Deserialization of Untrusted Data

Deserialization of Untrusted Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs