CVE-2026-17520: Newsletters < 4.17 - Unauthenticated API Access via Predictable API Key
Vulnerability summary
CVE-2026-17520 is a medium (CVSS 5.3) Inadequate Encryption Strength vulnerability in unknown newsletters. EPSS estimates a 0.12% chance of exploitation in the next 30 days, higher than 1.7% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 4.17.
Timeline
- 29-08-2026PublishedVulnerability first disclosed.
- 30-08-2026Last modifiedVulnerability information updated.
Description
The Newsletters WordPress plugin before 4.17 does not generate its API key using a sufficiently random source, deriving it from a publicly known value, allowing unauthenticated attackers to compute the key and perform privileged actions such as adding and deleting subscribers and sending emails, when the optional API has been enabled.
CVSS metrics
3 scores · 3 sources · 1 version- CVE.orgCNA4.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:LDiffers
- NVDNIST4.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:LDiffers
EPSS trend
Probability
0.12%
Chance of exploitation in the next 30 days
Percentile
2%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.12% on 24-09-2026
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-340Generation of Predictable Numbers or IdentifiersThe product uses a scheme that generates numbers or identifiers that are more predictable than required.
Affected systems
Unknown1 product
- newsletters< 4.17
Wordpress1 product
- newsletters-lite< 4.17
2 vendors · 2 products