CVE-2026-86824: Newsletter < 9.3.8 - Unauthenticated Subscriber PII Disclosure and Modification via Predictable Tracking Signature Key
Vulnerability summary
CVE-2026-86824 is a medium (CVSS 5.3) Inadequate Encryption Strength vulnerability in unknown newsletter. EPSS estimates a 0.15% chance of exploitation in the next 30 days, higher than 4.2% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 9.3.8.
Timeline
- 17-09-2026PublishedVulnerability first disclosed.
- 17-09-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 3 sources · 1 version- CVE.orgCNA4.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:NDiffers
- NVDNIST4.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:NDiffers
EPSS trend
Probability
0.15%
Chance of exploitation in the next 30 days
Percentile
4%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.15% on 25-09-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundExploit Reference (wpscan.com)
Maturity: unknown
Weaknesses
CWE · root cause- CWE-326Inadequate Encryption StrengthThe product stores or transmits sensitive data using an encryption scheme that is theoretically sound, but is not strong enough for the level of protection required.
- CWE-200Exposure of Sensitive Information to an Unauthorized ActorThe product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
Affected systems
Unknown1 product
- newsletter< 9.3.8
Wordpress1 product
- newsletter-email-mailing-list≤ 9.3.7 (fixed in 9.3.8)
2 vendors · 2 products