CVE-2026-12583
Unauth RCE via unsafe deserialization in Newsletters WordPress plugin <4.15
Is CVE-2026-12583 being exploited?
Not confirmed. CVE-2026-12583 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.55% probability of exploitation in the next 30 days.
How severe is CVE-2026-12583?
CVE-2026-12583 is rated High with a CVSS score of 8.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-12583?
Yes. A fix has been recorded for CVE-2026-12583. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-12583 affect?
CVE-2026-12583 affects Newsletters WordPress plugin < 4.15, WordPress sites using Newsletters plugin. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-12583?
Update Newsletters plugin to 4.15+ immediately; if unable, disable plugin and block public form endpoints.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated attackers can inject serialized PHP objects to write arbitrary files and achieve remote code execution on affected WordPress sites.
Immediate action required
- affected< 4.15
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.