CVE-2026-115274

Unbounded integer parsing in JSON.decode/1 enables CPU and memory exhaustion denial of service in Elixir

MEDIUM

6.9

CVSS Score

Published: October 30, 2026 at 08:57 AM UTC

Updated: October 30, 2026 at 07:39 PM UTC

1 product affected across 1 vendorElixir

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Severity

MEDIUM6.9

Exploit prediction

EPSS 0.5%

SSVC

PoC

Description

Improper Validation of Specified Quantity in Input vulnerability in the Elixir standard library's JSON module allows an unauthenticated attacker who supplies a JSON document to cause a denial of service through CPU and memory exhaustion. JSON.decode/1 and JSON.decode!/1 convert each integer literal with erlang:binary_to_integer/1 and do not bound its length. A literal of one million digits decodes successfully but costs 100 to 300 times as much CPU as a string of the same length, so one request body of a few megabytes holds a scheduler for about a second. A literal of more than about 1.29 million digits raises SystemLimitError. Applications generated by phx.new decode request bodies with JSON in Plug.Parsers, before routing and authentication. This issue affects elixir: from 1.18.0-rc.0 before 1.18.6, from 1.19.0-rc.0 before 1.19.7, and from 1.20.0-rc.0 before 1.20.5.