CVE-2026-88764: unknown simple membership Improper Privilege Management
Vulnerability summary
CVE-2026-88764 is a medium (CVSS 5.4) Improper Privilege Management vulnerability in unknown simple membership. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 12.9% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 4.7.8.
Timeline
- 13-09-2026PublishedVulnerability first disclosed.
- 13-09-2026Last modifiedVulnerability information updated.
Description
The Simple Membership WordPress plugin before 4.7.8 does not validate that the membership level supplied in a PayPal payment notification matches the level configured for the paid payment button, allowing members to pay for a lower-priced membership while being granted a higher, more privileged membership level.
CVSS metrics
3 scores · 3 sources · 1 version- NVDNIST5.4MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
- wordfenceSource4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:NDiffers
EPSS trend
Probability
0.23%
Chance of exploitation in the next 30 days
Percentile
13%
Versus all other CVEs
30-day change
+0.09 pp
From 0.14% on 19-09-2026
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-269Improper Privilege ManagementThe product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.
- CWE-862Missing AuthorizationThe product does not perform an authorization check when an actor attempts to access a resource or perform an action.
Affected systems
Unknown1 product
- simple membership< 4.7.8
Wordpress1 product
- simple-membership< 4.7.8
2 vendors · 2 products