An issue was discovered in BACKCLICK Professional 5.9.63. Due to the use of consecutive IDs in verification links, the newsletter sign-up functionality is vulnerable to the enumeration of subscribers' e-mail addresses. Furthermore, it is possible to subscribe and verify other persons' e-mail addresses to newsletters without their consent.
Severity
CVSS 3.1
5.3 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS
0.7% chance of exploitation in the next 30 days; higher than 52% of CVEs (scores of 2026-10-31)