CVE-2026-4020
Exploitation confirmed. First attested on 2026-06-17 by GCVE · kevintel, GCVE · shadowserver.
- Published2026-03-31
- WeaknessCWE-200
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
The Gravity SMTP plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 2.1.4. This is due to a REST API endpoint registered at /wp-json/gravitysmtp/v1/tests/mock-data with a permission_callback that unconditionally returns true, allowing any unauthenticated visitor to access it. When the ?page=gravitysmtp-settings query parameter is appended, the plugin's register_connector_data() method populates internal connector data, causing the endpoint to return approximately 365 KB of JSON containing the full System Report. This makes it possible for unauthenticated attackers to retrieve detailed system configuration data including PHP version, loaded extensions, web server version, document root path, database server type and version, WordPress version, all active plugins with versions, active theme, WordPress configuration details, database table names, and any API keys/tokens configured in the plugin.
Timeline
dates in UTC- 2026-03-3102:15CVE publishedNVD
- 2026-06-1710:28Listed as exploited by GCVEGCVE
- 2026-06-1710:28Exploitation first reportedGCVE
- 2026-10-2319:23First public proof of conceptPoC-in-GitHub
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-4020?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-4020?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-4020 yet.
Fix
No fix published by the sources we read yet. NVD record
Detection
read 2026-10-23 19:25 UTC- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- 2 repositories, unverifiedHORKimhab/CVE-2026-4020faizdotid/CVE-2026-4020 PoC-in-GitHub
Sources
- NVDCVE recordread 2026-10-23
- GCVEexploitation2026-06-17
- CISA-ADPSSVC decisionnone2026-04-02
- OpenCVESSVC decisionnone—
- CNACVSS 3.17.5read 2026-10-23
- CNAweakness (CWE)CWE-200read 2026-10-23
- FIRST EPSSEPSS score2.2 %2026-10-22
- PoC-in-GitHubproof of concept2read 2026-10-23
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Published
- 2026-03-31
- Last Modified
- 2026-06-17
- NVD status
- Deferred
Frequently asked questions
What is CVE-2026-4020?
Is CVE-2026-4020 actively exploited?
What is the CVSS score for CVE-2026-4020?
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Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.