CVE-2023-47163: Remarshal Remarshal Expands YAML Alias Nodes Vulnerability

HIGH
Advisory Identifier: GHSA-gw7g-qr8w-3448
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CVSS 7.5
CWE-400 CWE-674
Published
Advisory Summary

CVE-2023-47163 is a HIGH (CVSS 7.5) remarshal expands yaml alias nodes vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Remarshal libraries in the PyPI ecosystem. The issue involves remarshal expands yaml alias nodes unlimitedly, hence remarshal is vulnerable to billion laughs attack. Remediation is available by upgrading affected packages to version 0.17.1.

CVE-2023-47163 at a Glance

CVE Identifier CVE-2023-47163
GHSA Identifier GHSA-gw7g-qr8w-3448
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Remarshal
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2023-47163

To remediate this vulnerability, upgrade all affected Remarshal dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

remarshal fixed: 0.17.1 
pip install remarshal>=0.17.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show remarshal

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2023-47163, inspect your installed packages using pip:

pip show remarshal

Analyze the terminal output to locate any version of Remarshal in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.17.1), your application is affected.

Note: The pip show remarshal command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Remarshal, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Remarshal prior to v0.17.1 expands YAML alias nodes unlimitedly, hence Remarshal is vulnerable to Billion Laughs Attack. Processing untrusted YAML files may cause a denial-of-service (DoS) condition.

CVE-2023-47163 Affected Remarshal Versions

1 component(s)
Fixed Versions:
0.17.1
Product / Package Ecosystem Affected Versions Fixed Version
remarshal
pypi/remarshal
PyPI
< 0.17.1
0.17.1

References

NVD — CVE-2023-47163 NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-47163
Security Fix Commit FIX COMMIT
https://github.com/remarshal-project/remarshal/commit/fd6ac799a02f533c3fc243b49cdd6d21aa7ee494
Remarshal Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/remarshal/PYSEC-2023-236.yaml
Remarshal Source Repository REPOSITORY
https://github.com/remarshal-project/remarshal
Remarshal Release RELEASE
https://github.com/remarshal-project/remarshal/releases/tag/v0.17.1
jvn.jp/en/jp/jvn86156389 WEB
https://jvn.jp/en/jp/JVN86156389

Frequently Asked Questions

What is CVE-2023-47163?
CVE-2023-47163 is a security vulnerability in Remarshal involving Remarshal expands YAML alias nodes unlimitedly, hence Remarshal is vulnerable to Billion Laughs Attack under CWE-400: Uncontrolled Resource Consumption.
Which Remarshal versions are affected?
Affected versions include releases prior to 0.17.1 across affected packages: remarshal.
What version fixes CVE-2023-47163?
Upgrading to 0.17.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is remarshal affected?
Yes, remarshal is affected in releases prior to 0.17.1. Upgrade your dependency to 0.17.1 or later.
What is the CVSS score of CVE-2023-47163?
CVE-2023-47163 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2023-47163?
CVE-2023-47163 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check PyPI dependencies for CVE-2023-47163?
Run the dependency tree command: 'pip show remarshal'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-gw7g-qr8w-3448",
  "modified" : "2024-10-26T18:35:38Z",
  "published" : "2023-11-13T03:30:37Z",
  "aliases" : [ "CVE-2023-47163" ],
  "summary" : "Remarshal expands YAML alias nodes unlimitedly, hence Remarshal is vulnerable to Billion Laughs Attack",
  "details" : "Remarshal prior to v0.17.1 expands YAML alias nodes unlimitedly, hence Remarshal is vulnerable to Billion Laughs Attack. Processing untrusted YAML files may cause a denial-of-service (DoS) condition.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "remarshal"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.17.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-47163"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/remarshal-project/remarshal/commit/fd6ac799a02f533c3fc243b49cdd6d21aa7ee494"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/remarshal/PYSEC-2023-236.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/remarshal-project/remarshal"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/remarshal-project/remarshal/releases/tag/v0.17.1"
  }, {
    "type" : "WEB",
    "url" : "https://jvn.jp/en/jp/JVN86156389"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400", "CWE-674" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-11-14T22:19:05Z",
    "nvd_published_at" : "2023-11-13T03:15:09Z"
  }
}