Fastjson before 1.2.48 mishandles autoType because, when an @type key is in a JSON document, and the value of that key is the name of a Java class, there may be calls to certain public methods of that class. Depending on the behavior of those methods, there may be JNDI injection with an attacker-supplied payload located elsewhere in that JSON document. This was exploited in the wild in 2023 through 2025. NOTE: this issue exists because of an incomplete fix for CVE-2017-18349. Also, a later bypass is covered by CVE-2022-25845.
{
"github_reviewed_at": "2026-01-09T19:33:17Z",
"severity": "CRITICAL",
"cwe_ids": [
"CWE-829"
],
"nvd_published_at": "2026-01-09T07:16:02Z",
"github_reviewed": true
}