CVE-2026-59171: stleary JSON-java · Uncontrolled Resource Consumption
Affects stleary JSON-javaSource CVE Database V5
Not known to be exploited · CVSS 5.9 Medium.
Data as of 6 Nov 2026, 21:03 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 5.9 |
|---|
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 6 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| stlearyJSON-java | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade to JSON-java version 20260719 or later, which limits numeric conversion length and mitigates the vulnerability. No other configuration changes (such as strict mode or keep-strings) prevent exploitation. Patch status is confirmed by the introduction of the fix in version 20260719.
Description
CVE-2026-59171 is a vulnerability in the JSON-java library (stleary) affecting versions from 20150729 through 20260522. The flaw allows unbounded accumulation of numeric tokens in JSONTokener.nextSimpleValue, leading to excessive CPU consumption when converting large numeric literals. This can cause denial of service by blocking request-handling threads. The issue is not mitigated by strict mode or keep-strings settings. Version 20260719 introduces a limit on numeric conversion length to address this.
References
- github.com/stleary/JSON-java/security/advisories/GHSA-ghc9-756g-vrcv (opens in a new tab)
- github.com/stleary/JSON-java/pull/1065 (opens in a new tab)
- github.com/stleary/JSON-java/pull/1067 (opens in a new tab)
- github.com/stleary/JSON-java/commit/703ac34a55400f9c50889e3d0c778b6d7962e81c (opens in a new tab)
- github.com/stleary/JSON-java/commit/ab92bb9088a37f9e346cd1dda66f6a3c40a201e0 (opens in a new tab)
- github.com/stleary/JSON-java/commit/fce83c91bb229dde472283dea648a9a8955237fd (opens in a new tab)
- github.com/stleary/JSON-java/releases/tag/20260719 (opens in a new tab)