CVE-2026-59171

MEDIUMCVSS 5.9/10

Last modified

CVE-2026-59171 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. 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.

Description

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.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
stlearyJSON-java>= 20150729, < 20260719

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-59171?
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.
How severe is CVE-2026-59171?
CVE-2026-59171 has a CVSS score of 5.9/10 (MEDIUM severity).
How do I fix CVE-2026-59171?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST