CVE-2025-67221

The orjson.dumps function in orjson thru 3.11.4 does not limit recursion for deeply nested JSON documents

High · published January 22, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
49.7
In the wild
Unconfirmed
What it is

⚡ Deeply nested JSON documents can cause a meltdown! The orjson.dumps function in orjson up to version 3.11.4 lacks limits on recursion, potentially leading to high memory usage. 🔥 Think of it like a restaurant taking orders from a single customer but never stopping to check if that order has too many add-ons. If the customer keeps piling on requests, chaos ensues in the kitchen! An attacker could exploit this flaw to create a deeply nested JSON structure, overwhelming the server's memory and possibly causing a crash. This could lead to downtime or degraded performance, impacting your users and services.

Put simply

Think of it like a restaurant taking orders from a single customer but never stopping to check if that order has too many add-ons. If the customer keeps piling on requests, chaos ensues in the kitchen! The vulnerability lies in the orjson.dumps function which fails to restrict the depth of recursion for JSON documents, potentially leading to excessive memory use or Denial of Service (DoS).

What to do

An attacker could exploit this flaw to create a deeply nested JSON structure, overwhelming the server's memory and possibly causing a crash. This could lead to downtime or degraded performance, impacting your users and services. To mitigate this issue, upgrade to orjson version 3.11.5 or later immediately. Additionally, review your JSON handling processes to implement limits on recursion depth as a best practice. You can fix this! Get that upgrade done, and you'll have everything secured in no time. 🛡️

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00633 · 49.7th percentile
Published
2026-01-22T00:00Z
EPSS history
Timeline
  • 22 JAN 00:00Z
    The orjson.dumps function in orjson thru 3.11.4 does not limit recursion for deeply nested JSON documents
    cvelistv5