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CWE-693Weakness · CWE-693

CVE-2026-14440

MEDIUM · 6.8 CVSS v3.1 Published 2026-07-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
73/100
Remediation priority · Elevated
No privileges Zero-click 8 weeks old

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
Description: To issue and renew TLS certificates on behalf of customers, Cloudflare's Universal SSL feature automatically manages the CAA RRset for the customer's zone. This auto-managed RRset is permissive by design (e.g. 'issue "letsencrypt.org"' without parameters). On Universal SSL zones, Cloudflare's authoritative DNS serves this auto-managed RRset at query time, superseding any customer-configured CAA records on the zone. When a customer publishes a stricter CAA record using the RFC 8657 accounturi or validationmethods parameters, the Certificate Authority does not observe those parameters when evaluating the served RRset under RFC 8659. As a result, the RFC 8657 account-binding and validation-method-binding protections are not enforced end-to-end on Universal SSL zones. Successful exploitation could result in issuance of a browser-trusted TLS certificate to an attacker, enabling MITM against the affected domain. Exploitation is non-trivial in practice: an attacker would need to hold an ACME account at one of the Certificate Authorities in the served CAA RRset and to simultaneously satisfy domain control validation across the multiple geographically distinct Network Perspectives the CA relies on for Multi-Perspective Issuance Corroboration. Cloudflare prefixes are anycast-announced from hundreds of locations globally, raising the bar against single-vantage-point BGP hijacks. Any resulting misissuance of a browser-trusted certificate is subject to Certificate Transparency logging required by major browsers, and would be visible to CT monitoring. Mitigation:  Customers requiring strict RFC 8657 enforcement need to disable Universal SSL on the affected zone. Universal SSL's automatic CAA management and customer-set RFC 8657 accounturi and validationmethods enforcement are mutually exclusive by the nature of the issue, so there is no in-product workaround that preserves both.  Certificate Transparency monitoring is recommended for all customers as a general detection control. Credits: David Osipov (ORCID: https://orcid.org/0009-0005-2713-9242), independent researcher

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

Cloudflare's Universal SSL automatically manages CAA records for customer zones with permissive settings (e.g., 'issue letsencrypt.org'). When customers publish stricter RFC 8657 CAA records with accounturi or validationmethods parameters, Cloudflare's auto-managed RRset takes precedence at query time, causing the CA to ignore the stricter parameters. This breaks RFC 8657 account-binding and validation-method-binding protections, potentially allowing attackers to obtain browser-trusted TLS certificates for the domain.

MitigationCustomers requiring strict RFC 8657 enforcement must disable Universal SSL on affected zones; this is the only available workaround as Cloudflare's automatic CAA management and RFC 8657 parameter enforcement are mutually exclusive.

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
Adjacent
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/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. Verify Cloudflare is handling DNS for the domain
    Query the authoritative DNS servers for the domain's CAA records using 'dig +trace TYPE CAA domain.com' or check DNS resolution to confirm Cloudflare IPs
    Affected if The domain uses Cloudflare as its authoritative DNS provider
  2. Confirm Universal SSL is enabled on the zone
    Access Cloudflare Dashboard > SSL/TLS > Overview, or use Cloudflare API: GET /zones/{zone_id}/ssl_settings to check if universal_ssl is enabled
    Affected if Universal SSL is enabled and active for the zone
  3. Inspect existing CAA records for RFC 8657 parameters
    Run 'dig CAA yourdomain.com' or use a DNS lookup tool to retrieve all CAA records. Look for entries containing 'accounturi=' or 'validationmethods=' parameters which indicate RFC 8657 strict binding
    Affected if CAA records exist with accounturi or validationmethods parameters intended to enforce strict certificate issuance controls
  4. Check for Cloudflare auto-managed CAA records
    Compare CAA records retrieved directly from Cloudflare's nameservers versus the zone's configured record set. Cloudflare's auto-managed records may appear with issuer 'letsencrypt.org' or similar defaults that override stricter customer-defined records
    Affected if Cloudflare's auto-managed CAA records are present alongside or overriding the stricter RFC 8657 CAA records

A domain is affected if it uses Cloudflare with Universal SSL enabled AND has published RFC 8657 CAA records with accounturi or validationmethods parameters that are being overridden by Cloudflare's auto-managed CAA records.

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

Customers requiring strict RFC 8657 enforcement must disable Universal SSL on affected zones; this is the only available workaround as Cloudflare's automatic CAA management and RFC 8657 parameter enforcement are mutually exclusive.

Recommended fix High confidence
  1. 1. Log in to the Cloudflare dashboard
  2. 2. Select the affected domain/zone
  3. 3. Navigate to SSL/TLS > Universal SSL
  4. 4. Click 'Disable Universal SSL' or toggle the setting to off
  5. 5. Confirm the action when prompted
  6. 6. Immediately provision an alternative SSL certificate (e.g., Custom Certificate, Advanced Certificate) to maintain HTTPS availability
  7. 7. Configure custom CAA records with RFC 8657 parameters (accounturi and/or validationmethods) if strict account-binding or validation-method-binding is required
  8. 8. Monitor Certificate Transparency logs for the domain to detect any unauthorized certificate issuance
Caveat Disabling Universal SSL removes automatic certificate management; the customer must manually provision and renew certificates to maintain HTTPS service

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2026-14440 in production — separate from our analysis above.

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