Newsletter <= 9.3.9 - Unauthenticated Insufficiently Protected Credentials via '/tnp/l/' Click-Tracking REST Endpoint (Raw Subscriber Token Cookie Disclosure)
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | Newsletter – Send awesome emails from WordPress | <= 9.3.9 | 9.4.0 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N- Weakness (CWE)
CWE-522- Platform
- WordPress
- Package
Newsletter – Send awesome emails from WordPress- Disclosed
- 30.09.2026
- Updated
- 11.10.2026 10:23
Sources and licenses
Wordfence Intelligence - ed68a4ff-a2aa-4df7-96b1-f094bce4b9b7 - Wordfence Intelligence
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Copyright 2012-2026 Defiant Inc.
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Vulnerability history: Newsletter – Send awesome emails from WordPress
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 24
- First → latest
- 05.2013 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 4
- Medium 20
Disclosures per year
- 2017: 0
- 2018: 0
- 2019: 0
- 2020: 4
- 2021: 0
- 2022: 2
- 2023: 2
- 2024: 4
- 2025: 5
- 2026: 5
earlier: 2
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Newsletter <= 9.3.9 - Unauthenticated Insufficiently Protected Credentials via '/tnp/l/' Click-Tracking REST Endpoint (Raw Subscriber Token Cookie Disclosure) this entry
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