# CVE-2026-59171: JSON-java: JSONTokener Unbounded Numeric String Resource-Exhaustion DoS

Status: published. Published: 2026-11-06. Updated: 2026-11-06.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- stleary / JSON-java: >= 20150729, < 20260719 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 5.9 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-400, CWE-770

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/stleary/JSON-java/security/advisories/GHSA-ghc9-756g-vrcv (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/stleary/JSON-java/pull/1065 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/stleary/JSON-java/pull/1067 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/stleary/JSON-java/commit/703ac34a55400f9c50889e3d0c778b6d7962e81c (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/stleary/JSON-java/commit/ab92bb9088a37f9e346cd1dda66f6a3c40a201e0 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/stleary/JSON-java/commit/fce83c91bb229dde472283dea648a9a8955237fd (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/stleary/JSON-java/releases/tag/20260719 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-59171; retrieved 2026-11-06; source updated 2026-11-06

Revision: d0db43a506bda0f213cb7222f0b79aa8b422b26a798992c6759312b78468eb5a

Canonical: https://y2.dev/cve/CVE-2026-59171

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