# UltraJSON vulnerabilities

Source: https://junglewise.ai/threats/vendors/ultrajson  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Updated: 9 November 2026, 03:07 UTC. Rebuilt every hour.  
Data: https://junglewise.ai/threats/vendors/ultrajson.json  
License: CC BY 4.0 with a link back

Junglewise Threat Intelligence has tracked 4 vulnerabilities in UltraJSON: 0 in the last 7 days and 0 in the last 90 days, 0 of them critical and 0 exploited in the wild. The most recent, CVE-2026-54911, was published on 22 June 2026. 1 technology has a page of its own.

## Counts

- Last 7 days: 0
- Last 30 days: 0
- Last 90 days: 0
- All time: 4 (0 critical, 0 exploited in the wild)

## About UltraJSON

UltraJSON is an ultra fast JSON encoder and decoder written in C with bindings for Python.

## Latest UltraJSON vulnerabilities

- [CVE-2026-54911: UltraJSON improper input validation in ujson.dumps UTF-8 handling](https://junglewise.ai/threats/cve-2026-54911-ultrajson-improper-input-validation-in-ujson-dumps-utf-8-handling) (medium, CVSS 6.5, published 22 Jun 2026)
- [CVE-2026-44660: UltraJSON memory leak in ujson.dump on write failure](https://junglewise.ai/threats/cve-2026-44660-ultrajson-memory-leak-in-ujson-dump-on-write-failure) (high, CVSS 7.5, published 27 May 2026)
- [CVE-2026-32875: UltraJSON integer overflow in indent handling](https://junglewise.ai/threats/cve-2026-32875-ultrajson-integer-overflow-in-indent-handling) (high, CVSS 7.5, published 20 Mar 2026)
- [CVE-2026-32874: UltraJSON memory leak in JSON parsing of large integers](https://junglewise.ai/threats/cve-2026-32874-ultrajson-memory-leak-in-json-parsing-of-large-integers) (high, CVSS 7.5, published 20 Mar 2026)

## Most severe UltraJSON vulnerabilities

- [CVE-2026-32875: UltraJSON integer overflow in indent handling](https://junglewise.ai/threats/cve-2026-32875-ultrajson-integer-overflow-in-indent-handling) (high, CVSS 7.5, published 20 Mar 2026)
- [CVE-2026-32874: UltraJSON memory leak in JSON parsing of large integers](https://junglewise.ai/threats/cve-2026-32874-ultrajson-memory-leak-in-json-parsing-of-large-integers) (high, CVSS 7.5, published 20 Mar 2026)
- [CVE-2026-44660: UltraJSON memory leak in ujson.dump on write failure](https://junglewise.ai/threats/cve-2026-44660-ultrajson-memory-leak-in-ujson-dump-on-write-failure) (high, CVSS 7.5, published 27 May 2026)
- [CVE-2026-54911: UltraJSON improper input validation in ujson.dumps UTF-8 handling](https://junglewise.ai/threats/cve-2026-54911-ultrajson-improper-input-validation-in-ujson-dumps-utf-8-handling) (medium, CVSS 6.5, published 22 Jun 2026)

## Vulnerabilities per week

Nothing was published in the last eight weeks.

| Week of | Vulns | Critical | Exploited |
| --- | --- | --- | --- |
| 17 Aug 2026 | 0 | 0 | 0 |
| 24 Aug 2026 | 0 | 0 | 0 |
| 31 Aug 2026 | 0 | 0 | 0 |
| 7 Sep 2026 | 0 | 0 | 0 |
| 14 Sep 2026 | 0 | 0 | 0 |
| 21 Sep 2026 | 0 | 0 | 0 |
| 28 Sep 2026 | 0 | 0 | 0 |
| 5 Oct 2026 | 0 | 0 | 0 |
| 12 Oct 2026 | 0 | 0 | 0 |
| 19 Oct 2026 | 0 | 0 | 0 |
| 26 Oct 2026 | 0 | 0 | 0 |
| 2 Nov 2026 | 0 | 0 | 0 |
| 9 Nov 2026 | 0 | 0 | 0 |

## UltraJSON technologies

- [UltraJSON](https://junglewise.ai/threats/technologies/ultrajson): 4 vulnerabilities

## Sources

NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories. Rebuilt every hour. Cite as: Junglewise Threat Intelligence, "UltraJSON vulnerabilities", https://junglewise.ai/threats/vendors/ultrajson, 9 November 2026.