CVE-2026-19801: Auth Bypass (CVSS 4.3)

Description

The BetterLinks – Link Shortener, Link Cloaking, Redirects, Affiliate Link Manager & MCP plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 3.1.0. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for authenticated attackers, with subscriber-level access and above, to create arbitrary BetterLinks short URLs with attacker-controlled slugs and redirect destinations, enabling phishing and SEO abuse. Exploitation requires the Fluent Boards companion plugin to be installed and active (so that the FLUENT_BOARDS constant is defined), and is further facilitated by the betterlinks_admin_nonce nonce being emitted on every frontend page via wp_localize_script, making it accessible to any authenticated user.

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CVSS v3.1 Score

4.3

MEDIUM

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

EPSS — Exploit Prediction

0.0030

Probability of exploitation

0.22%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Other References

https://plugins.trac.wordpress.org/browser/betterlinks/tags/3.0.0/betterlinks.php#L254 https://plugins.trac.wordpress.org/browser/betterlinks/tags/3.0.0/includes/Admin/Ajax.php#L180 https://plugins.trac.wordpress.org/browser/betterlinks/tags/3.0.0/includes/Admin/Ajax.php#L99 https://plugins.trac.wordpress.org/browser/betterlinks/tags/3.1.0/betterlinks.php#L254 https://plugins.trac.wordpress.org/browser/betterlinks/tags/3.1.0/includes/Admin/Ajax.php#L180 https://plugins.trac.wordpress.org/browser/betterlinks/tags/3.1.0/includes/Admin/Ajax.php#L99 https://plugins.trac.wordpress.org/changeset?reponame=&old=3658390%40betterlinks&new=3658390%40betterlinks https://www.wordfence.com/threat-intel/vulnerabilities/id/faf44730-b975-4057-96dc-7284775500f9?source=cve

Frequently Asked Questions

What is CVE-2026-19801? +

The BetterLinks – Link Shortener, Link Cloaking, Redirects, Affiliate Link Manager & MCP plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 3.1.0. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for authenticated attackers, with subscriber-level access and above, to create arbitrary BetterLinks short URLs with attacker-controlled slugs and redirect destinations, enabling phishing and SEO abuse. Exploitation requires the Fluent Boards companion plugin to be installed and active (so that the FLUENT_BOARDS constant is defined), and is further facilitated by the betterlinks_admin_nonce nonce being emitted on every frontend page via wp_localize_script, making it accessible to any authenticated user. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-19801? +

CVE-2026-19801 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0030, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-19801? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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