CVE-2026-17559: unknown passster Missing Authorization
Vulnerability summary
CVE-2026-17559 is a medium (CVSS 5.3) Missing Authorization vulnerability in unknown passster. EPSS estimates a 0.35% chance of exploitation in the next 30 days, higher than 27.1% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 4.3.9.
Timeline
- 21-08-2026PublishedVulnerability first disclosed.
- 21-08-2026Last modifiedVulnerability information updated.
Description
The Passster WordPress plugin before 4.3.9 does not correctly match its own public endpoint paths when deciding which REST API requests may bypass global password protection, comparing them as an unanchored substring of the request URI rather than against the resolved route, allowing an unauthenticated attacker to read the content of globally password-protected posts and pages.
CVSS metrics
3 scores · 3 sources · 1 version- NVDNIST5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- wordfenceSource5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS trend
Probability
0.35%
Chance of exploitation in the next 30 days
Percentile
27%
Versus all other CVEs
30-day change
+0.09 pp
From 0.26% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (wpscan.com)
Maturity: unknown
Weaknesses
CWE · root cause- CWE-862Missing AuthorizationThe product does not perform an authorization check when an actor attempts to access a resource or perform an action.
- CWE-863Incorrect AuthorizationThe product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Affected systems
Unknown1 product
- passster≥ 4.3.3, < 4.3.9
Wordpress1 product
- content-protector< 4.3.9
2 vendors · 2 products