No. Junglewise Threat Intelligence has no report of CVE-2018-18307 being exploited in the wild.
How severe is CVE-2018-18307?
Low severity, with a CVSS score of 3.1, published 14 May 2022.
Which products and versions are affected?
alchemy_cms (RubyGems). The advisory does not name versions.
Is there a fix for CVE-2018-18307?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2018-18307?
Check whether you run alchemy_cms (RubyGems). Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.