dbcve.org
NetApplication · Golang

CVE-2026-42502

MEDIUM · 6.1 CVSS v3.1 Published 2026-05-22
Fix available
A fix is available. Upgrade to 0.55.0 or later.
See remediation →
68/100
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
Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.

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 · moderate confidence

This is an HTML parser differential vulnerability where the Render component parses HTML differently than sanitization libraries expect, creating an unexpected HTML tree structure. This allows attackers to craft HTML that passes sanitizer checks but renders as malicious content when processed by Render, enabling XSS attacks.

MitigationReview and update HTML sanitization logic to account for the Render component's parsing behavior; implement additional output encoding layers and validate sanitized output against the actual rendered DOM.

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

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
NetApplication
Affected:< 0.55.0

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
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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 if Golang Net is used
    Review your project's go.mod file for the 'net' Go standard library package or any direct golang.org/x/net dependencies
    Affected if The project imports golang.org/x/net or uses net/html for HTML processing
  2. Check the installed version of golang.org/x/net
    Run 'go list -m golang.org/x/net' or 'go mod tidy && go list -m all' to list all dependencies with versions
    Affected if The version listed is less than 0.55.0
  3. Identify HTML rendering code paths
    Search source code for usage of net/html Parse functions, template.HTML usage, or any custom HTML rendering that processes user input
    Affected if Code processes raw HTML input through golang.org/x/net/html or net/html parsing
  4. Check for HTML sanitization in place
    Review the codebase for usage of third-party sanitization libraries (DOMPurify, sanitize-html) or custom sanitization logic applied before rendering
    Affected if HTML input is rendered without sanitization or uses a sanitizer that may be bypassed by this vulnerability
  5. Verify if user-controlled HTML reaches the parser
    Audit input handling: trace any request parameters, form inputs, or API payloads that flow into HTML parsing and rendering
    Affected if Untrusted HTML input from users or external sources is parsed and rendered without re-validation after sanitization

You are affected if your application uses golang.org/x/net version less than 0.55.0 and processes untrusted HTML input through the Render component without additional sanitization verification.

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
Upgrade available Upgrade to 0.55.0 or later
Fixed in 0.55.0
Interim mitigation

Review and update HTML sanitization logic to account for the Render component's parsing behavior; implement additional output encoding layers and validate sanitized output against the actual rendered DOM.

Recommended fix Moderate confidence

Net >= 0.55.0

  1. Check the current version of the Net package in your go.mod file (likely golang.org/x/net or similar)
  2. Update the Net package dependency to version 0.55.0 or later using: go get golang.org/x/[email protected]
  3. Run go mod tidy to clean up dependencies and verify the update
  4. Rebuild your application and run tests to ensure the fix works correctly
  5. If your application sanitizes HTML input before rendering, verify that the XSS vulnerability is now properly mitigated

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

Fix this in Net Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,224.

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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-2026-42502 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data