dbcve.org
NetApplication · Golang

CVE-2026-25681

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 a cross-site scripting (XSS) vulnerability in a Render library where parsing arbitrary HTML results in an unexpected HTML tree structure. Attackers can craft malicious HTML that bypasses sanitization filters, allowing XSS execution when the sanitized content is rendered in applications.

MitigationUpdate the Render library to the latest patched version and re-validate that sanitization properly handles edge cases in the HTML parser output.

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. Check golang.org/x/net package version
    Run 'go list -m golang.org/x/net' in your project directory or inspect your go.mod file for the 'golang.org/x/net' entry
    Affected if The version listed is less than 0.55.0 (e.g., v0.54.0, v0.50.0, etc.)
  2. Identify HTML parsing usage
    Search your codebase for imports of 'golang.org/x/net/html' or 'html/template' packages, and review any code that calls html.Parse() or uses template.HTML rendering
    Affected if Your application parses or renders user-supplied HTML content using these packages
  3. Verify HTML sanitization is in place
    Search for usage of HTML sanitization libraries such as 'github.com/microcosm-cc/bluemonday', 'github.com/ssor/newsanitizer' or similar, and locate where user HTML input is sanitized before rendering
    Affected if Your application renders user-provided HTML and relies on sanitization to prevent XSS without additional context-aware escaping
  4. Test sanitization against tree structure bypasses
    If sanitization exists, review the sanitizer's documentation or test with edge-case HTML that produces unexpected DOM trees (e.g., deeply nested tags, misplaced closing tags, unusual attribute combinations)
    Affected if The sanitizer has not been tested against malformed HTML tree structures or specifically validated for CVE-2026-25681 bypass scenarios

You are affected if golang.org/x/net is below version 0.55.0 AND your application parses/renders user-supplied HTML with sanitization that has not been validated against this specific tree structure bypass vulnerability.

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

Update the Render library to the latest patched version and re-validate that sanitization properly handles edge cases in the HTML parser output.

Recommended fix Moderate confidence

0.55.0

  1. Run `go get -u example.com/net@latest` or specify the fixed version directly with `go get -u example.com/[email protected]`
  2. Verify the upgrade completed successfully by checking go.mod
  3. Run your test suite to ensure the upgrade does not break existing functionality
  4. Rebuild and deploy your application
Caveat Review the Net package release notes for v0.55.0 to check for any breaking changes before upgrading

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

Fix this in Net Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.

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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-2026-25681 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