aeson was vulnerable to hash flooding (a.k.a. hash DoS). The issue is a consequence of the HashMap implementation from unordered-containers. It results in a denial of service through CPU consumption. This technique has been used in real-world attacks against a variety of languages, libraries and frameworks over the years.
{
"osvs": "https://raw.githubusercontent.com/haskell/security-advisories/refs/heads/generated/osv-export",
"home": "https://haskell.github.io/security-advisories",
"repository": "https://github.com/haskell/security-advisories"
}