CVE-2026-42458: Magento LTS Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-x8jv-q8j2-487c
Share
CWE-87
Published
Advisory Summary

CVE-2026-42458 is a MODERATE cross-site scripting vulnerability (CWE-87: Improper Neutralization of Alternate XSS Syntax) affecting Magento LTS libraries in the Packagist ecosystem. The issue involves reflected xss - import -> data flow (profiles). Remediation is available by upgrading affected packages to version 20.18.0.

CVE-2026-42458 at a Glance

CVE Identifier CVE-2026-42458
GHSA Identifier GHSA-x8jv-q8j2-487c
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-87: Improper Neutralization of Alternate XSS Syntax
Affected Product Magento LTS
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-42458

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

openmage/magento-lts fixed: 20.18.0 
Upgrade openmage/magento-lts to 20.18.0
Verify Direct and Transitive Dependencies

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

inspect dependencies for openmage/magento-lts

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-42458, inspect your project dependencies for Magento LTS:

inspect dependencies for openmage/magento-lts

Analyze the terminal output to locate any version of Magento LTS in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 20.18.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-87: Improper Neutralization of Alternate XSS Syntax, where the product does not neutralize or incorrectly neutralizes user-controlled input for alternate script syntax. In Magento LTS, 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

A reflected XSS vulnerability was found under admin panel -> System -> Import/Export -> Dataflow - Profiles. ## Steps to produce + Login to the admin panel + Go to the path `System -> Import/Export -> Dataflow - Profiles` + Select profile direction as `Import`. + Click on `Import Customers` + Upload the file. File Link: [customer_20260212_204335.csv](https://github.com/user-attachments/files/25629638/customer_20260212_204335.csv) + Go back to `Run profile`. + Select the uploaded file and Click on `Run in Popup`. + One can see a URL like this ``` https://demo-admin.openmage.org/index.php/admin/system_convert_gui/run/id/6/key/40dbbb2e93f45f0463c57ff733352f4f/files/import-20260215151125-1_customer_20260212_204335.csv/ ``` + One can see the filename getting reflection in HTML tags. + Inject an HTML tag and observe. ``` https://demo-admin.openmage.org/index.php/admin/system_convert_gui/run/id/6/key/40dbbb2e93f45f0463c57ff733352f4f/files/"><h3>hacked</h3>/ ``` <img width="1796" height="302" alt="image (3)" src="https://github.com/user-attachments/assets/502330b0-fa73-4b90-a81f-6216a98e474a" /> + One can see the tag is getting executed. + Proceed for XSS. ``` https://demo-admin.openmage.org/index.php/admin/system_convert_gui/run/id/6/key/40dbbb2e93f45f0463c57ff733352f4f/files/%3CScRiPt%20%3Eprompt(document.cookie)%3C%2FScRiPt%3E ``` <img width="1670" height="562" alt="image (4)" src="https://github.com/user-attachments/assets/98a75081-fa8c-4483-9078-0ab5e7e14e4d" /> + There is an XSS popup. ## Impact Cookie stealing, JS deface, many more

CVE-2026-42458 Affected Magento LTS Versions

1 component(s)
Fixed Versions:
20.18.0
Product / Package Ecosystem Affected Versions Fixed Version
openmage/magento-lts
 Packagist
< 20.18.0
20.18.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/OpenMage/magento-lts/security/advisories/GHSA-x8jv-q8j2-487c
NVD — CVE-2026-42458 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42458
Magento LTS Source Repository REPOSITORY
https://github.com/OpenMage/magento-lts

Frequently Asked Questions

What is CVE-2026-42458?
CVE-2026-42458 is a security vulnerability in Magento LTS involving Reflected XSS - Import -> Data Flow (profiles) under CWE-87: Improper Neutralization of Alternate XSS Syntax.
Which Magento LTS versions are affected?
Affected versions include releases prior to 20.18.0 across affected packages: openmage/magento-lts.
What version fixes CVE-2026-42458?
Upgrading to 20.18.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is openmage/magento-lts affected?
Yes, openmage/magento-lts is affected in releases prior to 20.18.0. Upgrade your dependency to 20.18.0 or later.
What CWE is associated with CVE-2026-42458?
CVE-2026-42458 is classified under CWE-87: Improper Neutralization of Alternate XSS Syntax (The product does not neutralize or incorrectly neutralizes user-controlled input for alternate script syntax.).
How can I check Packagist dependencies for CVE-2026-42458?
Run the dependency tree command: 'inspect dependencies for openmage/magento-lts'. 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-x8jv-q8j2-487c",
  "modified" : "2026-05-15T23:49:07Z",
  "published" : "2026-05-06T20:57:37Z",
  "aliases" : [ "CVE-2026-42458" ],
  "summary" : "Magento LTS: Reflected XSS - Import -> Data Flow (profiles) ",
  "details" : "A reflected XSS vulnerability was found under admin panel ->  System -> Import/Export -> Dataflow -  Profiles.\n\n## Steps to produce\n\n+ Login to  the admin panel \n\n+ Go to the path   `System -> Import/Export -> Dataflow -  Profiles`\n\n+ Select profile direction as `Import`.\n\n+ Click on `Import Customers` \n\n+ Upload the file.\n\nFile Link: [customer_20260212_204335.csv](https://github.com/user-attachments/files/25629638/customer_20260212_204335.csv)\n\n+ Go back to `Run profile`.\n\n+ Select the uploaded file and Click on `Run in Popup`.\n\n+ One can see a URL like this \n\n```\nhttps://demo-admin.openmage.org/index.php/admin/system_convert_gui/run/id/6/key/40dbbb2e93f45f0463c57ff733352f4f/files/import-20260215151125-1_customer_20260212_204335.csv/\n```\n\n\n+ One can see the filename getting reflection in HTML tags.\n\n+ Inject an HTML tag and observe.\n\n```\nhttps://demo-admin.openmage.org/index.php/admin/system_convert_gui/run/id/6/key/40dbbb2e93f45f0463c57ff733352f4f/files/\"><h3>hacked</h3>/\n``` \n\n<img width=\"1796\" height=\"302\" alt=\"image (3)\" src=\"https://github.com/user-attachments/assets/502330b0-fa73-4b90-a81f-6216a98e474a\" />\n\n+ One can see the tag is getting executed.\n\n+  Proceed for XSS.\n\n```\nhttps://demo-admin.openmage.org/index.php/admin/system_convert_gui/run/id/6/key/40dbbb2e93f45f0463c57ff733352f4f/files/%3CScRiPt%20%3Eprompt(document.cookie)%3C%2FScRiPt%3E\n```\n\n<img width=\"1670\" height=\"562\" alt=\"image (4)\" src=\"https://github.com/user-attachments/assets/98a75081-fa8c-4483-9078-0ab5e7e14e4d\" />\n\n\n+ There is an XSS popup.\n\n## Impact\n\nCookie stealing, JS deface, many more",
  "severity" : [ {
    "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" : "Packagist",
      "name" : "openmage/magento-lts"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "20.18.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 20.17.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/OpenMage/magento-lts/security/advisories/GHSA-x8jv-q8j2-487c"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-42458"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/OpenMage/magento-lts"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-87" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-06T20:57:37Z",
    "nvd_published_at" : "2026-05-15T17:16:46Z"
  }
}