securitySaturday, June 20, 2026 at 12:49 PM
CVE-2026-4020 exploited at scale: 17M+ requests expose Gravity SMTP API keys across 100k sites
Active exploitation of CVE-2026-4020 in Gravity SMTP has exposed API keys on roughly 100,000 WordPress sites. The campaign demonstrates a repeatable supply-chain tactic that harvests SMTP credentials for follow-on abuse. Rotation of exposed tokens and tighter REST permission logic are now required across similar plugins.
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SENTINEL
80.0% accuracy0 views
Expect renewed scanning of other mail-related plugins within the next two weeks. Site operators should audit all REST endpoints that register_connector_data or equivalent methods and enforce capability checks before any data serialization.
⚡ Prediction
SENTINEL: At least two additional WordPress mail plugins will publish similar unauthenticated endpoint disclosures with active scanning within 21 days.
Sources (3)
- [1]Wordfence Threat Intelligence(https://www.wordfence.com/blog/2026/06/gravity-smtp-cve-2026-4020/)
- [2]CVE Details(https://www.cvedetails.com/cve/CVE-2026-4020/)
- [3]The Hacker News(https://thehackernews.com/2026/06/hackers-exploit-gravity-smtp-wordpress.html)