How severe is CVE-2026-42238?

CVE-2026-42238 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-42238 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42238?

CVE-2026-42238 affects Nginxui Nginx Ui. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42238?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-42238 have an EU (EUVD) identifier?

Yes. CVE-2026-42238 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27141.

When was CVE-2026-42238 published?

CVE-2026-42238 was published on 2026-05-04 and last updated on 2026-06-17.

CVE-2026-42238

CVE-2026-42238 is a critical-severity vulnerability in Nginxui Nginx Ui with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 9.0
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-27141
Weakness: CWE-94
Affected product: Nginxui Nginx Ui
Published: 2026-05-04
Last modified: 2026-06-17

Description

Nginx UI is a web user interface for the Nginx web server. Prior to version 2.3.8, nginx-ui exposes a backup restore endpoint (POST /api/restore) that is completely unauthenticated during the first 10 minutes after process startup on any fresh installation. An unauthenticated remote attacker can upload a crafted backup archive that overwrites the application's configuration file (app.ini) and SQLite database. Because the attacker controls the restored app.ini, they can inject an arbitrary OS command into the TestConfigCmd setting. After the application automatically restarts to apply the restored config, a single follow-up request triggers that command as the user running nginx-ui — typically root in Docker deployments. This issue has been patched in version 2.3.8.

Frequently asked questions

What is CVE-2026-42238?: Nginx UI is a web user interface for the Nginx web server. Prior to version 2.3.8, nginx-ui exposes a backup restore endpoint (POST /api/restore) that is completely unauthenticated during the first 10 minutes after process startup on any fresh installation. An unauthenticated remote attacker can upload a crafted backup archive that overwrites the application's configuration file (app.ini) and SQLite database. Because the attacker controls the restored app.ini, they can inject an arbitrary OS command into the TestConfigCmd setting. After the application automatically restarts to apply the restored config, a single follow-up request triggers that command as the user running nginx-ui — typically root in Docker deployments. This issue has been patched in version 2.3.8.
How severe is CVE-2026-42238?: CVE-2026-42238 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-42238 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42238?: CVE-2026-42238 affects Nginxui Nginx Ui. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42238?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-42238 have an EU (EUVD) identifier?: Yes. CVE-2026-42238 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27141.
When was CVE-2026-42238 published?: CVE-2026-42238 was published on 2026-05-04 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nginxui:nginx_ui:*:*:*:*:*:*:*:*

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