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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-3438

MEDIUM · 5.1 CVSS v4.0 Published 2026-04-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A reflected cross-site scripting vulnerability exists in Sonatype Nexus Repository versions 3.0.0 through 3.90.2 that allows unauthenticated remote attackers to execute arbitrary JavaScript in a victim's browser through a specially crafted URL. Exploitation requires user interaction.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A reflected cross-site scripting (XSS) vulnerability in Sonatype Nexus Repository 3 versions 3.0.0 through 3.90.2 allows unauthenticated remote attackers to inject arbitrary JavaScript into victim browsers through specially crafted URLs, requiring user interaction (e.g., clicking a malicious link).

MitigationUpgrade to Nexus Repository 3 version 3.91.0 or later to obtain the vendor patch; as an interim control, deploy WAF rules to detect and block XSS payloads in URL parameters.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
Authentication
X
User interaction
A
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed Nexus Repository version
    Log into the Nexus Repository administrative web interface and navigate to the System > Information page, or query the Nexus API endpoint at /service/siesta/rest/v1/system/info to retrieve the running version number
    Affected if The displayed version falls within the range 3.0.0 through 3.90.2 inclusive
  2. Confirm the exact version number
    Record the full version string shown in the system information page or API response; ensure it matches the 3.x.x format and compare the numeric version against the upper bound of 3.90.2
    Affected if The version number is 3.90.2 or earlier (3.0.0 through 3.90.2)
  3. Verify the web application is accessible
    Confirm that the Nexus Repository web interface is running and accessible on its configured HTTP/HTTPS port; this is required for the reflected XSS to be exploitable
    Affected if The web application is exposed and the version is within the affected range

The environment is affected if Nexus Repository 3.x is installed and the running version falls between 3.0.0 and 3.90.2 inclusive.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Nexus Repository 3 version 3.91.0 or later to obtain the vendor patch; as an interim control, deploy WAF rules to detect and block XSS payloads in URL parameters.

Recommended fix Moderate confidence

Nexus Repository 3.91.0 or later

  1. Upgrade Sonatype Nexus Repository 3 from any version between 3.0.0 and 3.90.2 to version 3.91.0 or later
  2. After upgrading, verify the installation by logging into the Nexus Repository web interface
  3. Confirm that the reflected XSS vulnerability is remediated by testing that special characters in URLs are properly escaped
Caveat Review Nexus Repository 3.91.0 release notes for any compatibility changes or deprecations before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-3438 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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