serialize-javascript prior to 3.1.0 allows remote attackers to inject arbitrary code via the function "deleteFunctions" within "index.js".

An object such as {"foo": /1"/, "bar": "a\"@__R-<UID>-0__@"} was serialized as {"foo": /1"/, "bar": "a\/1"/}, which allows an attacker to escape the bar key. This requires the attacker to control the values of both foo and bar and guess the value of <UID>. The UID has a keyspace of approximately 4 billion making it a realistic network attack.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-7660
• yahoo/serialize-javascript@f21a6fb