CVE-2026-92537: Credential Exposure (CVSS 5.3)

Description

The Newsletter – Send awesome emails from WordPress plugin for WordPress is vulnerable to Insufficiently Protected Credentials in all versions up to, and including, 9.3.9 The plugin's public click-tracking REST route `/tnp/l/` is registered with `permission_callback => '__return_true'` and, upon receiving a valid keyed-MD5 signature, calls `set_user_cookie()`, which emits a `Set-Cookie: newsletter=<id>-<raw_token>` response header to the requester because the subscriber object loaded via `get_user()` lacks the `_trusted` property, causing `get_user_key()` to return the raw token column value instead of its MD5-masked variant. This makes it possible for unauthenticated attackers who obtain any signed click-tracking URL for a target subscriber to receive that subscriber's permanent raw authentication cookie, which they can then use to export the subscriber's full PII record via the JSON profile-export endpoint (`?na=px`), rewrite the subscriber's stored profile (`?na=ps`), and silently unsubscribe the subscriber via the RFC-8058 one-click endpoint (`?na=ocu`), none of which require a nonce, password, or email challenge. Signed tracking URLs are embedded in every external link of every newsletter delivered to a subscriber, carry no timestamp, and never expire until the site's relink key rotates, meaning that any party who observes such a URL — through a forwarded email, a shared inbox, a mail-gateway log, or Referer headers on the redirect target, which has no Referrer-Policy set — can replay it indefinitely to obtain the victim's credential.

Is your site exposed to CVE-2026-92537?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

5.3

MEDIUM

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

EPSS — Exploit Prediction

0.0032

Probability of exploitation

0.23%

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-522 CWE-522

References

Other References

https://plugins.trac.wordpress.org/browser/newsletter/tags/9.3.9/includes/module-base.php#L1209 https://plugins.trac.wordpress.org/browser/newsletter/tags/9.3.9/includes/module-base.php#L441 https://plugins.trac.wordpress.org/browser/newsletter/tags/9.3.9/includes/module.php#L403 https://plugins.trac.wordpress.org/browser/newsletter/tags/9.3.9/statistics/statistics.php#L107 https://plugins.trac.wordpress.org/browser/newsletter/tags/9.3.9/statistics/statistics.php#L174 https://plugins.trac.wordpress.org/browser/newsletter/tags/9.3.9/statistics/statistics.php#L335 https://plugins.trac.wordpress.org/changeset?reponame=&new=3709894%40newsletter%2Ftags%2F9.4.0&old=3695457%40newsletter%2Ftags%2F9.3.9 https://www.wordfence.com/threat-intel/vulnerabilities/id/ed68a4ff-a2aa-4df7-96b1-f094bce4b9b7?source=cve

Frequently Asked Questions

What is CVE-2026-92537? +

The Newsletter – Send awesome emails from WordPress plugin for WordPress is vulnerable to Insufficiently Protected Credentials in all versions up to, and including, 9.3.9 The plugin's public click-tracking REST route `/tnp/l/` is registered with `permission_callback => '__return_true'` and, upon receiving a valid keyed-MD5 signature, calls `set_user_cookie()`, which emits a `Set-Cookie: newsletter=<id>-<raw_token>` response header to the requester because the subscriber object loaded via `get_user()` lacks the `_trusted` property, causing `get_user_key()` to return the raw token column value instead of its MD5-masked variant. This makes it possible for unauthenticated attackers who obtain any signed click-tracking URL for a target subscriber to receive that subscriber's permanent raw authentication cookie, which they can then use to export the subscriber's full PII record via the JSON profile-export endpoint (`?na=px`), rewrite the subscriber's stored profile (`?na=ps`), and silently unsubscribe the subscriber via the RFC-8058 one-click endpoint (`?na=ocu`), none of which require a nonce, password, or email challenge. Signed tracking URLs are embedded in every external link of every newsletter delivered to a subscriber, carry no timestamp, and never expire until the site's relink key rotates, meaning that any party who observes such a URL — through a forwarded email, a shared inbox, a mail-gateway log, or Referer headers on the redirect target, which has no Referrer-Policy set — can replay it indefinitely to obtain the victim's credential. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-92537? +

CVE-2026-92537 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0032, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-92537? +

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.

Related Vulnerabilities

CVE-2025-15621

Insufficiently Protected Credentials in Sparx Systems Pty Ltd. Sparx Enterprise Architect. Client does not verify the receiver of OAuth2 credentials …

CVE-2025-15622

Insufficiently Protected Credentials vulnerability in Sparx Systems Pty Ltd. Sparx Enterprise Architect. Client reveals plaintext OAuth2 client secretDesktop client decodes …

CVE-2026-4387

StrongDM Desktop Application before 23.74.0 (Desktop Client before 53.77.0) on Microsoft Windows stores authentication state, including a JSON Web Token …

CVE-2026-46458

ICU Scandinavia Boomerang is vulnerable to an information disclosure flaw where sensitive credential files are exposed via static HTTP. This …

CVE-2026-8368

LWP::UserAgent versions before 6.83 for Perl leak Authorization and Proxy-Authorization headers on cross-origin redirects. On a 3xx response, the redirect …

CVE-2024-12799

Insufficiently Protected Credentials vulnerability in OpenText Identity Manager Advanced Edition on Windows, Linux, 64 bit allows Privilege Abuse. This vulnerability …

CVE-2026-92537