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Vulnerability Database · PyPI · Package report

ujson: vulnerability history, versions and safety

ujson is a package in the PyPI ecosystem. Vulert records 16 vulnerabilities for it across 57 releases, from Jul 2021 to Jul 2026. Each vulnerability names the versions it affects, the fixed version to move to, and a workaround where no fix has been published.

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16 vulnerabilities recorded H6 M3 U7
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0 with no fix published

Every vulnerability has a patched version to move to.

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10 in the last 12 months

Most recent disclosure 06 Jul 2026.

See the disclosure history →
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0 malicious-package vulnerabilities

No published version shipped hostile code.

See all ujson vulnerabilities

Vulert verdict on ujson 6.0.0 i

Updated on 23 Oct 2026

Good news: 6.0.0, the version you would install today, has no known vulnerabilities. Older releases do — the table below lists all 16.

Package health score 67/100
  • Security Unfixed issues
  • Maintenance Sustainable
  • Popularity Key ecosystem project
  • Community Moderate

What to do: Stay on 6.0.0 or newer. This can change: a vulnerability disclosed tomorrow can affect 6.0.0 too — Vulert watches the package and alerts you if that happens. Monitor it with Vulert →

  • Current release 6.0.0 — unaffected i
  • Vulnerabilities on record 16 over 4 years · 10 in the last year i
  • Latest disclosure 06 Jul 2026 i
  • Highest CVSS 8.7 i
  • With no published fix 0 i
  • Depended on by 2,870 packages i
  • Stars 4,500 i
  • OpenSSF scorecard 6/10 i
  • Last release 1 month ago i
  • Licence BSD-3-Clause AND TCL i

Version list, release dates, licence and dependants published by PyPI, refreshed 23 Oct 2026. Licence information is not legal advice.

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01 Versions

Which versions are affected

Every version Vulert tracks for ujson, newest first, with the vulnerabilities recorded against each one. A version showing none has no vulnerability in the Vulert database — open it for the full picture on that release.

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Version Released Vulert vulnerabilities Licence Fix published Details
6.0.0 04 Sep 2026 none BSD-3-Clause AND TCL — Details →
5.13.0 14 Jun 2026 none BSD-3-Clause AND TCL — Details →
5.12.1 05 May 2026 M1 U1 BSD-3-Clause AND TCL Yes Details →
5.12.0 11 Mar 2026 H1 M1 U2 BSD-3-Clause AND TCL Yes Details →
5.11.0 20 Aug 2025 H3 M1 U4 — Yes Details →
5.10.0 14 May 2024 H3 M1 U4 BSD-3-Clause Yes Details →
5.9.0 10 Dec 2023 H3 M1 U4 BSD-3-Clause Yes Details →
5.8.0 11 Jun 2023 H3 M1 U4 BSD-3-Clause Yes Details →
5.7.0 06 Jan 2023 H3 M1 U4 BSD-3-Clause Yes Details →
5.6.0 01 Dec 2022 H3 M1 U4 BSD-3-Clause Yes Details →
5.5.0 15 Sep 2022 H3 M1 U4 BSD-3-Clause Yes Details →
5.4.0 02 Jul 2022 H3 M1 U4 BSD-3-Clause Yes Details →
5.3.0 18 May 2022 H3 M2 U5 BSD-3-Clause Yes Details →
5.2.0 05 Apr 2022 H3 M2 U5 BSD-3-Clause Yes Details →
5.1.0 20 Dec 2021 H5 M3 U5 BSD-3-Clause Yes Details →
5.0.0 16 Dec 2021 H3 M3 U5 BSD-3-Clause Yes Details →
4.3.0 22 Nov 2021 H3 M3 U5 BSD-3-Clause Yes Details →
4.2.0 22 Sep 2021 H3 M3 U5 BSD-3-Clause Yes Details →
4.1.0 16 Aug 2021 H3 M3 U5 BSD-3-Clause Yes Details →
4.0.2 21 Jan 2021 H3 M3 U5 non-standard Yes Details →
4.0.1 09 Oct 2020 H3 M3 U4 non-standard Yes Details →
4.0.0 07 Oct 2020 H3 M3 U4 non-standard Yes Details →
3.2.0 08 Sep 2020 H3 M3 U4 non-standard Yes Details →
3.1.0 02 Aug 2020 H3 M3 U4 non-standard Yes Details →
3.0.0 03 Jun 2020 H3 M3 U4 non-standard Yes Details →
2.0.3 24 Mar 2020 H3 M3 U4 non-standard Yes Details →
2.0.2 15 Mar 2020 H3 M3 U4 non-standard Yes Details →
2.0.1 14 Mar 2020 H3 M3 U4 non-standard Yes Details →
2.0.0 07 Mar 2020 H3 M3 U4 non-standard Yes Details →
1.35.0 20 Jan 2016 H2 M3 U4 non-standard Yes Details →
1.34.0 30 Nov 2015 H2 M3 U4 non-standard Yes Details →
1.33.0 11 Jun 2013 H2 M2 U4 non-standard Yes Details →
1.30.0 18 Feb 2013 H2 M2 U4 non-standard Yes Details →
1.23.0 06 Nov 2012 H2 M2 U4 non-standard Yes Details →
1.22.0 01 Oct 2012 H2 M2 U4 non-standard Yes Details →
1.21.0 01 Oct 2012 H2 M2 U4 non-standard Yes Details →
1.19.0 26 Jun 2012 H2 M2 U4 non-standard Yes Details →
1.18.0 07 Feb 2012 H2 M2 U4 non-standard Yes Details →
1.15.0 14 Dec 2011 H2 M2 U4 non-standard Yes Details →
1.9.0 19 Sep 2011 H2 M2 U4 non-standard Yes Details →
1.8.0 09 Sep 2011 H2 M2 U4 non-standard Yes Details →
1.6.0 17 Aug 2011 H2 M2 U4 non-standard Yes Details →
1.4.0 16 Jun 2011 H2 M2 U4 non-standard Yes Details →
1.19.win32-py2.7 — H2 M2 U4 — Yes Details →
1.19.win32-py3.2 — H2 M2 U4 — Yes Details →
1.21.win32-py2.6 — H2 M2 U4 — Yes Details →
1.21.win32-py2.7 — H2 M2 U4 — Yes Details →
1.21.win32-py3.2 — H2 M2 U4 — Yes Details →
1.22.win32-py2.6 — H2 M2 U4 — Yes Details →
1.22.win32-py2.7 — H2 M2 U4 — Yes Details →
1.22.win32-py3.2 — H2 M2 U4 — Yes Details →
1.23.win32-py2.6 — H2 M2 U4 — Yes Details →
1.23.win32-py2.7 — H2 M2 U4 — Yes Details →
1.23.win32-py3.2 — H2 M2 U4 — Yes Details →
1.30.win32-py2.6 — H2 M2 U4 — Yes Details →
1.30.win32-py2.7 — H2 M2 U4 — Yes Details →
1.30.win32-py3.3 — H2 M2 U4 — Yes Details →
1.33.win32-py2.6 — H2 M2 U4 — Yes Details →
1.33.win32-py3.3 — H2 M2 U4 — Yes Details →

All 59 versions Vulert tracks for this package. Severity counts are the vulnerabilities recorded against that exact release.

02 Disclosure history

How often vulnerabilities are recorded

  • 2021 1
  • 2022 5
  • 2026 10

Counted by the year Vulert recorded each vulnerability — the same date the table below shows as disclosed. 10 of the 16 were recorded in the last 12 months.

03 Vulnerabilities

Recorded vulnerabilities for ujson

The 5 most severe of 16 vulnerabilities recorded for this package

Search all 16 in the database →
Vulnerability Severity Fixed version ↓ Disclosed ↓
CVE-2026-44660: UltraJSON Memory Leak on Write Failure in ujson.dump() 8.7 high 5.12.1 12 May 2026
CVE-2026-32874: ujson Memory Leak Vulnerability in JSON Parsing of Large Integers 7.5 high 5.12.0 20 Mar 2026
CVE-2026-32875: ujson Buffer Overflow and Infinite Loop Vulnerability 7.5 high 5.12.0 20 Mar 2026
CVE-2022-31116: ujson Package - Incorrect Handling of Invalid Surrogate Pair Characters 7.5 high 5.4.0 06 Jul 2026
CVE-2022-31116: ujson - Incorrect handling of invalid surrogate pair characters 7.5 high 5.4.0 05 Jul 2022

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Updated: 23/Oct/2026 · Vulnerabilities in our DB: 524315

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Questions

About ujson

Is ujson safe to use?

Vulert records 16 vulnerabilities for ujson in PyPI: 0 critical, 6 high, 3 medium and 0 low, plus 7 not yet rated. Every one of them has a published fix, so the practical answer is to run a supported release and keep it patched.

What is ujson's Vulert package health score?

Vulert scores ujson 67/100, which reads as usable, but worth attention. The score weighs the vulnerability record (40), maintenance and release cadence (25), adoption from dependents and stars (20) and community signals such as the OpenSSF scorecard and forks (15).

Is the latest version of ujson affected?

No. 6.0.0, the version you would install today, has no vulnerabilities on record against it. Earlier releases do — the version table above lists each release with what affects it.

Which version of ujson should I use?

6.0.0 is the version Vulert recommends for the affected releases. The version table above lists every release with the vulnerabilities recorded against it, so you can confirm the range you actually run.

How many vulnerabilities does ujson have?

16 vulnerabilities are recorded for ujson in the PyPI ecosystem: 0 critical, 6 high, 3 medium and 0 low, plus 7 not yet rated. The ledger on this page lists the same counts next to the date of the most recent disclosure.

How often are new ujson vulnerabilities disclosed?

10 vulnerabilities were recorded for ujson in the last 12 months, and the oldest entry in this database dates to 11 Jul 2021. Recency matters more than a lifetime total: it shows how actively new issues are being disclosed for the package you are considering.

Which versions of ujson are affected?

Each vulnerability on this page lists the affected version range and the fixed version to move to. Open the vulnerability for the version you actually run — fixes are specific to a release line, not to the package as a whole.

How do I monitor ujson for upcoming vulnerabilities?

Upload the manifest or SBOM for your application at vulert.com/scanner and Vulert keeps checking the ujson version you actually run against new disclosures, then alerts you when one affects it. There is no installation and no source-code access required.