Deserialization in Newsletters

CVE-2026-16267

The Newsletters WordPress plugin before 4.16 does not restrict the classes allowed when unserialising a value taken from a public form submission, allowing unauthenticated attackers to inject arbitrary PHP objects.

Vulnerability class: Insecure Deserialization

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (39.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-16267: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

  • Newsletters — versions 0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-16267?
CVE-2026-16267 is a high-severity vulnerability in Newsletters, classified under Deserialization of Untrusted Data. CVSS score: 8.1/10. Published 2026-08-08.
How severe is CVE-2026-16267?
High severity. CVSS v3 base score is 8.1 out of 10.