How severe is CVE-2026-42458?

No CVSS score has been assigned to CVE-2026-42458 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-42458?

CVE-2026-42458 affects the following packages: openmage/magento-lts (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-42458?

Update openmage/magento-lts to 20.18.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42458 is resolved across your whole dependency graph.

How do I detect CVE-2026-42458 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openmage/magento-lts, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-42458 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-42458 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-42458 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-42458?

CVE-2026-42458 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 25th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-42458?

CVE-2026-42458 is classified as CWE-87 (CWE-87). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-42458 published, and has it been updated?

CVE-2026-42458 was published on May 15, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-42458 — magento-lts

CVE-2026-42458 is a CWE-87 vulnerability in openmage/magento-lts. A fix is available for openmage/magento-lts — see the affected versions and patch details below.

Magento LTS: Reflected XSS - Import -> Data Flow (profiles)

Also known asGHSA-x8jv-q8j2-487c

Published

May 15, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-42458.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk-0.12%

Lower risk than most CVEs25th percentile — riskier than 25% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐘openmage/magento-lts

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

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

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>/

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

There is an XSS popup.

Impact

Cookie stealing, JS deface, many more

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`openmage/magento-lts`	all versions	20.18.0`composer require openmage/magento-lts:^20.18.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openmage/magento-lts, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update openmage/magento-lts to 20.18.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42458 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

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