Is CVE-2026-12583 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-12583 being exploited in the wild.

How severe is CVE-2026-12583?

Informational severity, with a CVSS score of 8.1, published 14 July 2026.

Is there a fix for CVE-2026-12583?

A patch was published on 2026-07-14: Fixed in version 4.15 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-12583 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-12583?

Check whether you run Tribulant Newsletters at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-12583: Tribulant Newsletters PHP object injection in subscriber custom fields

CVE-2026-12583 · Severity: info · CVSS 8.1 · Published 2026-07-14

The Newsletters plugin for WordPress, which manages email marketing and subscriber lists, contains a critical security flaw. An unauthenticated attacker can use a public subscription form to submit malicious data that, when processed by the server, allows them to create unauthorized files or execute arbitrary code. This could lead to a full takeover of the website, theft of subscriber data, or a complete service outage.

Technologies: Tribulant Newsletters. Vendors: Tribulant.

Quick answers

Is CVE-2026-12583 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-12583 being exploited in the wild.
How severe is CVE-2026-12583?: Informational severity, with a CVSS score of 8.1, published 14 July 2026.
Which products and versions are affected?: Tribulant Newsletters < 4.15.
Is there a fix for CVE-2026-12583?: A patch was published on 2026-07-14: Fixed in version 4.15 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-12583 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-12583?: Check whether you run Tribulant Newsletters at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The Newsletters plugin fails to properly validate or sanitize untrusted input stored through public subscription forms, leading to a PHP Object Injection vulnerability. An unauthenticated attacker can submit a serialized PHP object via a custom text field in the opt-in form. When the attacker later views a newsletter online using their subscriber ID and authkey, the plugin deserializes the stored field value. By utilizing a POP (Property-Oriented Programming) gadget chain present in the bundled GuzzleHttp library, an attacker can trigger a file-write primitive to create a web shell and achieve remote code execution. This issue is fixed in version 4.15.

Affected products

Tribulant Newsletters (newsletters-lite) < 4.15

Timeline

2026-06-23: disclosed: Publicly published by WPScan
2026-07-14: advisory: NVD publication date
2026-07-14: patched: Fixed in version 4.15

References

https://wpscan.com/vulnerability/e4c44105-f43d-4dff-8487-7d8ae2691c4e/

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