# ujson (PyPI) vulnerabilities Source: https://junglewise.ai/threats/technologies/ujson Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats Updated: 13 November 2026, 03:07 UTC. Rebuilt every hour. Data: https://junglewise.ai/threats/technologies/ujson.json License: CC BY 4.0 with a link back Junglewise Threat Intelligence has tracked 9 vulnerabilities in ujson (PyPI): 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-2022-31116, was published on 6 July 2026. ## Counts - Last 7 days: 0 - Last 30 days: 0 - Last 90 days: 0 - All time: 9 (0 critical, 0 exploited in the wild) ## About ujson (PyPI) ujson is a Python library for fast JSON encoding and decoding. ## Latest ujson (PyPI) vulnerabilities - [CVE-2022-31116: PYSEC-2026-1057 - Incorrect handling of invalid surrogate pair characters](https://junglewise.ai/threats/cve-2022-31116-incorrect-handling-of-invalid-surrogate-pair-characters) (low, CVSS 3.1, published 6 Jul 2026) - [CVE-2022-31117: PYSEC-2026-1056 - Potential double free of buffer during string decoding](https://junglewise.ai/threats/cve-2022-31117-potential-double-free-of-buffer-during-string-decoding) (low, CVSS 3.1, published 6 Jul 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) - [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) - [OSV-2021-1809 - Heap-buffer-overflow in ujson.cpython-38-x86_64-linux-gnu.so](https://junglewise.ai/threats/osv-2021-1809-heap-buffer-overflow-in-ujson-cpython-38-x86-64-linux-gnu-0780b9df) (info, published 25 Feb 2022) - [CVE-2021-45958: UltraJSON vulnerable to Out-of-bounds Write](https://junglewise.ai/threats/cve-2021-45958-ultrajson-vulnerable-to-out-of-bounds-write) (low, CVSS 3.1, published 1 Jan 2022) - [OSV-2021-955 - Stack-buffer-overflow in Buffer_AppendIndentUnchecked](https://junglewise.ai/threats/osv-2021-955-stack-buffer-overflow-in-buffer-appendindentunchecked-c5a59190) (info, published 11 Jul 2021) ## Most severe ujson (PyPI) 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) - [CVE-2022-31116: PYSEC-2026-1057 - Incorrect handling of invalid surrogate pair characters](https://junglewise.ai/threats/cve-2022-31116-incorrect-handling-of-invalid-surrogate-pair-characters) (low, CVSS 3.1, published 6 Jul 2026) - [CVE-2022-31117: PYSEC-2026-1056 - Potential double free of buffer during string decoding](https://junglewise.ai/threats/cve-2022-31117-potential-double-free-of-buffer-during-string-decoding) (low, CVSS 3.1, published 6 Jul 2026) - [CVE-2021-45958: UltraJSON vulnerable to Out-of-bounds Write](https://junglewise.ai/threats/cve-2021-45958-ultrajson-vulnerable-to-out-of-bounds-write) (low, CVSS 3.1, published 1 Jan 2022) - [OSV-2021-1809 - Heap-buffer-overflow in ujson.cpython-38-x86_64-linux-gnu.so](https://junglewise.ai/threats/osv-2021-1809-heap-buffer-overflow-in-ujson-cpython-38-x86-64-linux-gnu-0780b9df) (info, published 25 Feb 2022) - [OSV-2021-955 - Stack-buffer-overflow in Buffer_AppendIndentUnchecked](https://junglewise.ai/threats/osv-2021-955-stack-buffer-overflow-in-buffer-appendindentunchecked-c5a59190) (info, published 11 Jul 2021) ## 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 | ## Other PyPI technologies - [tensorflow (PyPI)](https://junglewise.ai/threats/technologies/pypi-tensorflow): 435 vulnerabilities - [tensorflow-cpu (PyPI)](https://junglewise.ai/threats/technologies/tensorflow-cpu): 430 vulnerabilities - [tensorflow-gpu (PyPI)](https://junglewise.ai/threats/technologies/tensorflow-gpu): 427 vulnerabilities - [open-webui (PyPI)](https://junglewise.ai/threats/technologies/open-webui): 177 vulnerabilities - [Django (PyPI)](https://junglewise.ai/threats/technologies/django): 173 vulnerabilities - [apache-airflow (PyPI)](https://junglewise.ai/threats/technologies/apache-airflow): 159 vulnerabilities - [pillow (PyPI)](https://junglewise.ai/threats/technologies/pillow): 125 vulnerabilities - [praisonai (PyPI)](https://junglewise.ai/threats/technologies/pypi-praisonai): 120 vulnerabilities - [vllm (PyPI)](https://junglewise.ai/threats/technologies/pypi-vllm): 117 vulnerabilities - [plone (PyPI)](https://junglewise.ai/threats/technologies/pypi-plone): 101 vulnerabilities - [mlflow (PyPI)](https://junglewise.ai/threats/technologies/mlflow): 88 vulnerabilities - [picklescan (PyPI)](https://junglewise.ai/threats/technologies/picklescan): 86 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, "ujson (PyPI) vulnerabilities", https://junglewise.ai/threats/technologies/ujson, 13 November 2026.