CVE-2022-31116: Ujson Incorrect Handling Of Invalid Surrogate Vulnerability

HIGH
Advisory Identifier: GHSA-wpqr-jcpx-745r
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CVSS 7.5
CWE-670
Published
Advisory Summary

CVE-2022-31116 is a HIGH (CVSS 7.5) incorrect handling of invalid surrogate vulnerability (CWE-670: Always-Incorrect Control Flow Implementation) affecting Ujson libraries in the PyPI ecosystem. The issue involves incorrect handling of invalid surrogate pair characters. Remediation is available by upgrading affected packages to version 5.4.0.

CVE-2022-31116 at a Glance

CVE Identifier CVE-2022-31116
GHSA Identifier GHSA-wpqr-jcpx-745r
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-670: Always-Incorrect Control Flow Implementation
Affected Product Ujson
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-2022-31116

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

ujson fixed: 5.4.0 
pip install ujson>=5.4.0
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 ujson

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2022-31116, inspect your installed packages using pip:

pip show ujson

Analyze the terminal output to locate any version of Ujson in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.4.0), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-670: Always-Incorrect Control Flow Implementation, where the code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated. In Ujson, 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

### Impact _What kind of vulnerability is it? Who is impacted?_ Anyone parsing JSON from an untrusted source is vulnerable. JSON strings that contain escaped surrogate characters not part of a proper surrogate pair were decoded incorrectly. Besides corrupting strings, this allowed for potential key confusion and value overwriting in dictionaries. Examples: ```python # An unpaired high surrogate character is ignored. >>> ujson.loads(r'"\uD800"') '' >>> ujson.loads(r'"\uD800hello"') 'hello' # An unpaired low surrogate character is preserved. >>> ujson.loads(r'"\uDC00"') '\udc00' # A pair of surrogates with additional non surrogate characters pair up in spite of being invalid. >>> ujson.loads(r'"\uD800foo bar\uDC00"') 'foo bar๐€€' ``` ### Patches _Has the problem been patched? What versions should users upgrade to?_ Users should upgrade to UltraJSON 5.4.0. From version 5.4.0, UltraJSON decodes lone surrogates in the same way as the standard library's `json` module does, preserving them in the parsed output: ```python3 >>> ujson.loads(r'"\uD800"') '\ud800' >>> ujson.loads(r'"\uD800hello"') '\ud800hello' >>> ujson.loads(r'"\uDC00"') '\udc00' >>> ujson.loads(r'"\uD800foo bar\uDC00"') '\ud800foo bar\udc00' ``` ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ Short of switching to an entirely different JSON library, there are no safe alternatives to upgrading. ### For more information If you have any questions or comments about this advisory: * Open an issue in [UltraJSON](http://github.com/ultrajson/ultrajson/issues)

CVE-2022-31116 Affected Ujson Versions

1 component(s)
Fixed Versions:
5.4.0
Product / Package Ecosystem Affected Versions Fixed Version
ujson
pypi/ujson
PyPI
< 5.4.0
5.4.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/ultrajson/ultrajson/security/advisories/GHSA-wpqr-jcpx-745r
NVD โ€” CVE-2022-31116 NVD
https://nvd.nist.gov/vuln/detail/CVE-2022-31116
Security Fix Commit FIX COMMIT
https://github.com/ultrajson/ultrajson/commit/67ec07183342589d602e0fcf7bb1ff3e19272687
Ujson Source Repository REPOSITORY
https://github.com/ultrajson/ultrajson
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NAU5N4A7EUK2AMUCOLYDD5ARXAJYZBD2
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OPPU5FZP3LCTXYORFH7NHUMYA5X66IA7

Frequently Asked Questions

What is CVE-2022-31116?
CVE-2022-31116 is a security vulnerability in Ujson involving Incorrect handling of invalid surrogate pair characters under CWE-670: Always-Incorrect Control Flow Implementation.
Which Ujson versions are affected?
Affected versions include releases prior to 5.4.0 across affected packages: ujson.
What version fixes CVE-2022-31116?
Upgrading to 5.4.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is ujson affected?
Yes, ujson is affected in releases prior to 5.4.0. Upgrade your dependency to 5.4.0 or later.
What is the CVSS score of CVE-2022-31116?
CVE-2022-31116 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-2022-31116?
CVE-2022-31116 is classified under CWE-670: Always-Incorrect Control Flow Implementation (The code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated.).
How can I check PyPI dependencies for CVE-2022-31116?
Run the dependency tree command: 'pip show ujson'. 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-wpqr-jcpx-745r",
  "modified" : "2022-08-05T13:56:18Z",
  "published" : "2022-07-05T21:06:00Z",
  "aliases" : [ "CVE-2022-31116" ],
  "summary" : "Incorrect handling of invalid surrogate pair characters",
  "details" : "### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\nAnyone parsing JSON from an untrusted source is vulnerable.\n\nJSON strings that contain escaped surrogate characters not part of a proper surrogate pair were decoded incorrectly. Besides corrupting strings, this allowed for potential key confusion and value overwriting in dictionaries.\n\nExamples:\n\n```python\n# An unpaired high surrogate character is ignored.\n>>> ujson.loads(r'\"\\uD800\"')\n''\n>>> ujson.loads(r'\"\\uD800hello\"')\n'hello'\n\n# An unpaired low surrogate character is preserved.\n>>> ujson.loads(r'\"\\uDC00\"')\n'\\udc00'\n\n# A pair of surrogates with additional non surrogate characters pair up in spite of being invalid.\n>>> ujson.loads(r'\"\\uD800foo bar\\uDC00\"')\n'foo bar๐€€'\n```\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\n\nUsers should upgrade to UltraJSON 5.4.0.\n\nFrom version 5.4.0, UltraJSON decodes lone surrogates in the same way as the standard library's `json` module does, preserving them in the parsed output:\n\n```python3\n>>> ujson.loads(r'\"\\uD800\"')\n'\\ud800'\n>>> ujson.loads(r'\"\\uD800hello\"')\n'\\ud800hello'\n>>> ujson.loads(r'\"\\uDC00\"')\n'\\udc00'\n>>> ujson.loads(r'\"\\uD800foo bar\\uDC00\"')\n'\\ud800foo bar\\udc00'\n```\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\n\nShort of switching to an entirely different JSON library, there are no safe alternatives to upgrading.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [UltraJSON](http://github.com/ultrajson/ultrajson/issues)\n",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "ujson"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.4.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/ultrajson/ultrajson/security/advisories/GHSA-wpqr-jcpx-745r"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2022-31116"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ultrajson/ultrajson/commit/67ec07183342589d602e0fcf7bb1ff3e19272687"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ultrajson/ultrajson"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NAU5N4A7EUK2AMUCOLYDD5ARXAJYZBD2"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OPPU5FZP3LCTXYORFH7NHUMYA5X66IA7"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-670" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-07-05T21:06:00Z",
    "nvd_published_at" : "2022-07-05T18:15:00Z"
  }
}