CVE-2023-28370: Tornado Open Redirect Vulnerability

MODERATE
Advisory Identifier: GHSA-hj3f-6gcp-jg8j
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CVSS 6.1
CWE-601
Published
Advisory Summary

CVE-2023-28370 is a MODERATE (CVSS 6.1) open redirect vulnerability (CWE-601: URL Redirection to Untrusted Site ('Open Redirect')) affecting Tornado libraries in the PyPI ecosystem. The issue involves open redirect in tornado. Remediation is available by upgrading affected packages to version 6.3.2.

CVE-2023-28370 at a Glance

CVE Identifier CVE-2023-28370
GHSA Identifier GHSA-hj3f-6gcp-jg8j
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
Affected Product Tornado
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.1

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:R/S:C/C:L/I:L/A:N).

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

How to Fix CVE-2023-28370

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

tornado fixed: 6.3.2 
pip install tornado>=6.3.2
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 tornado

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2023-28370, inspect your installed packages using pip:

pip show tornado

Analyze the terminal output to locate any version of Tornado in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 6.3.2), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect'), where the web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect. In Tornado, 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

Open redirect vulnerability in Tornado versions 6.3.1 and earlier allows a remote unauthenticated attacker to redirect a user to an arbitrary web site and conduct a phishing attack by having user access a specially crafted URL.

CVE-2023-28370 Affected Tornado Versions

1 component(s)
Fixed Versions:
6.3.2
Product / Package Ecosystem Affected Versions Fixed Version
tornado
pypi/tornado
PyPI
< 6.3.2
6.3.2

References

NVD — CVE-2023-28370 NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-28370
Security Fix Commit FIX COMMIT
https://github.com/tornadoweb/tornado/commit/32ad07c54e607839273b4e1819c347f5c8976b2f
Tornado Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/tornado/PYSEC-2023-75.yaml
Tornado Source Repository REPOSITORY
https://github.com/tornadoweb/tornado
Tornado Release RELEASE
https://github.com/tornadoweb/tornado/releases/tag/v6.3.2
jvn.jp/en/jp/jvn45127776 WEB
https://jvn.jp/en/jp/JVN45127776
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2025/01/msg00000.html

Frequently Asked Questions

What is CVE-2023-28370?
CVE-2023-28370 is a security vulnerability in Tornado involving Open redirect in Tornado under CWE-601: URL Redirection to Untrusted Site ('Open Redirect').
Which Tornado versions are affected?
Affected versions include releases prior to 6.3.2 across affected packages: tornado.
What version fixes CVE-2023-28370?
Upgrading to 6.3.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is tornado affected?
Yes, tornado is affected in releases prior to 6.3.2. Upgrade your dependency to 6.3.2 or later.
What is the CVSS score of CVE-2023-28370?
CVE-2023-28370 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2023-28370?
CVE-2023-28370 is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect') (The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.).
How can I check PyPI dependencies for CVE-2023-28370?
Run the dependency tree command: 'pip show tornado'. 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-hj3f-6gcp-jg8j",
  "modified" : "2025-11-04T16:44:12Z",
  "published" : "2023-05-25T12:30:16Z",
  "aliases" : [ "CVE-2023-28370" ],
  "summary" : "Open redirect in Tornado",
  "details" : "Open redirect vulnerability in Tornado versions 6.3.1 and earlier allows a remote unauthenticated attacker to redirect a user to an arbitrary web site and conduct a phishing attack by having user access a specially crafted URL.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "tornado"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "6.3.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-28370"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/tornadoweb/tornado/commit/32ad07c54e607839273b4e1819c347f5c8976b2f"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/tornado/PYSEC-2023-75.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/tornadoweb/tornado"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/tornadoweb/tornado/releases/tag/v6.3.2"
  }, {
    "type" : "WEB",
    "url" : "https://jvn.jp/en/jp/JVN45127776"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2025/01/msg00000.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-601" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-05-25T17:00:25Z",
    "nvd_published_at" : "2023-05-25T10:15:09Z"
  }
}