CVE-2026-14440

Cloudflare Universal SSL automatically managed CAA RRset supersedes customer-configured CAA records

Cloudflare Universal SSL

CVSS

7.6High

ExploitationPublic exploit codeCISA's assessment says proof of concept code is public, assessed 2 Jul 2026. Not in the KEV catalogCISA via CVE List

Exploit odds (EPSS)0.20%Chance of exploitation activity in the next 30 days, higher than 9% of CVEs. Scored 25 Oct 2026FIRST EPSS

Fixed inNone listedNo source names a fixed version. Check the vendor advisory below

Published1 Jul 2026Updated 2 Jul 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

Timeline

1 Jul 2026, 22:35 UTCPublishedCVE List
25 Oct 2026, 19:02 UTCExploit code publicGitHub proof-of-concept repositories

Reports 1

1 outlet mention it. Reports are not confirmation; each links to its source.

Ghost-Bx1/Cloudflare-Exploits-CVE-2026-14440-CVE-2026-3125-CVE-2025-0651: PoC e exploits para CVE-2026-14440 (Universal SSL CAA Bypass), CVE-2026-3125 (OpenNext SSRF), CVE-2025-0651 (WARP Windows Privesc) | By Gh0st-Bx1GitHub proof-of-concept repositories, 25 Oct 2026Exploit code

Description

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

Text from CVE List

Affected versions 1

Universal SSLaffected: all versions through currentCVE List