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VulnerabilityPublished

CVE-2026-42221: 0xJacky nginx-ui · Missing Authentication

Affects 0xJacky nginx-uiSource CVE Database V5

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Not known to be exploited · public detection template (Nuclei) · CVSS 8.1 High : upgrade to 2.3.8 soon.

Data as of 31 Oct 2026, 20:20 UTC

CVSS 3.1 base score
8.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
1.3% chance of exploitation in 30 days – higher than 71% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.3.8
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 May 2026

  2. Weaponized: evidence found.

    Public exploit code: GitHub proofs of concept

  3. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  4. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.

What to do

Upgrade nginx-ui and 0xjacky/nginx-ui to 2.3.8.

Affected software

ProductAffectedFixed in
0xJackynginx-uiAffected
  • >=2.0.0 <2.3.8
Fixed in
  • 2.3.8
GitHub0xjacky/nginx-uipkg:github/0xjacky/nginx-uiOther threatsAffected
  • >=2.0.0 <2.3.8
Fixed in
  • 2.3.8

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

This vulnerability is patched in nginx-ui version 2.3.8. Users should upgrade to version 2.3.8 or later to remediate this issue. Until patched, restrict network access to the installation endpoint to trusted users only to reduce exposure.

Description

CVE-2026-42221 is a high-severity vulnerability in 0xJacky's nginx-ui versions 2.0.0 up to but not including 2.3.8. It allows an unauthenticated remote attacker to claim the initial administrator account during the first-run setup by accessing the public /api/install endpoint without authentication. This leads to permanent takeover of the initial instance by setting the admin email, username, and password. The vulnerability arises because the installation endpoint lacks authentication, and encryption only protects data in transit, not the authorization of the installer. This issue has been fixed in version 2.3.

References

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