Advanced Google reCAPTCHA: Authentication Bypass Using an Alternate Path or Channel
CVE-2026-5415 is a high-severity authentication bypass using an alternate path or channel vulnerability in Advanced Google reCAPTCHA from WebFactory, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected Advanced Google reCAPTCHA versions: 5.38 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.54% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Advanced Google reCAPTCHA you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Webfactory | Advanced Google reCAPTCHA | 5.38 and earlier | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (wordfence.com).
Official description
The WP Captcha PRO (the premium version of the Advanced Google reCAPTCHA plugin, both have the same slug) plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.38. This is due to the ajax_run_tool() AJAX handler relying solely on a nonce check (check_ajax_referer) for security without performing any capability check, combined with the create_temporary_link tool allowing the generation of passwordless login links for arbitrary users, and the handle_temporary_links() function authenticating visitors via these links without any additional authorization validation. The required nonce is exposed to all authenticated backend users (including Subscribers) via wp_localize_script() on all non-settings admin pages when the plugin's welcome pointer has not been dismissed. This makes it possible for authenticated attackers, with Subscriber-level access and above, to bypass normal authentication and log in as any user, including Administrators, resulting in complete account takeover.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass Using an Alternate Path or Channel
The product requires authentication, but the product has an alternate path or channel that does not require authentication.
How developers prevent this class of flaw
- Funnel all access through a single choke point to simplify how users can access a resource. For every access, perform a check to determine if the user has permissions to access the resource.
More Authentication Bypass Using an Alternate Path or Channel vulnerabilities (CWE-288)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Advanced Google reCAPTCHA
- 8.8 High severity
Recent Authentication Bypass Using an Alternate Path or Channel vulnerabilities
- 7.1 High severity
- 7.5 High severity
- 9.8 Critical severity
- 9.3 Critical severity
- 9.3 Critical severity
- 7.5 High severity
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