An issue was discovered in the cache crate through 2020-11-24 for Rust. There are unconditional implementations of Send and Sync for Cache<K>.
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-36448.json"
[ { "events": [ { "introduced": "0" }, { "last_affected": "2020-11-24" } ] } ]