CVE-2026-59171

MEDIUM 5.9

JSON-java: JSONTokener Unbounded Numeric String Resource-Exhaustion DoS

CVSS Score

5.9

EPSS Score

0.0%

EPSS Percentile

0th

JSON-java is a reference implementation of a JSON package in Java. From version 20150729 through 20260522, JSONTokener.nextSimpleValue can accumulate unbounded numeric tokens before JSONObject.stringToNumber passes them to BigInteger or BigDecimal conversion without a length limit. An application that parses attacker-controlled JSON or XML through JSONObject, JSONArray, or XML.toJSONObject can spend super-linear CPU time converting a sufficiently long numeric literal, blocking request-handling threads and causing denial of service. Strict mode and keep-strings settings in JSONParserConfiguration do not prevent the affected conversion path. Version 20260719 limits numeric conversion length.

CWE	CWE-400 CWE-770
Vendor	stleary
Product	json-java
Published	Nov 6, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

stleary / JSON-java

>= 20150729, < 20260719

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/stleary/JSON-java/security/advisories/GHSA-ghc9-756g-vrcv github.com: https://github.com/stleary/JSON-java/pull/1065 github.com: https://github.com/stleary/JSON-java/pull/1067 github.com: https://github.com/stleary/JSON-java/commit/703ac34a55400f9c50889e3d0c778b6d7962e81c github.com: https://github.com/stleary/JSON-java/commit/ab92bb9088a37f9e346cd1dda66f6a3c40a201e0 github.com: https://github.com/stleary/JSON-java/commit/fce83c91bb229dde472283dea648a9a8955237fd github.com: https://github.com/stleary/JSON-java/releases/tag/20260719