How severe is CVE-2022-31117?

CVE-2022-31117 has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2022-31117?

CVE-2022-31117 affects the following packages: ujson (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2022-31117?

Update ujson to 5.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-31117 is resolved across your whole dependency graph.

How do I detect CVE-2022-31117 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ujson, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2022-31117 if there is no patch (or I can't update yet)?

Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.

Is CVE-2022-31117 actively exploited in the wild?

No public exploit code has been indexed for CVE-2022-31117 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2022-31117?

CVE-2022-31117 has an EPSS (Exploit Prediction Scoring System) score of 1.9%, placing it in the 80th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2022-31117?

CVE-2022-31117 is classified as CWE-415 (CWE-415). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2022-31117 published, and has it been updated?

CVE-2022-31117 was published on July 5, 2022 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

MEDIUM severity

CVE-2022-31117 — ujson

MEDIUMFix: ultrajson/ultrajson@9c20de0

CVE-2022-31117 is a medium-severity (CVSS 5.9) CWE-415 vulnerability in ujson. A fix is available for ujson — see the affected versions and patch details below.

Double free of buffer during string decoding in ujson

Also known asGHSA-fm67-cv37-96ffPYSEC-2026-1056

Published

Jul 5, 2022

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2022-31117.

EPSS Exploitation Probability

via FIRST.org ↗

1.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs80th percentile — riskier than 80% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐍ujson

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

What kind of vulnerability is it? Who is impacted?

When an error occurs while reallocating the buffer for string decoding, the buffer gets freed twice.

Due to how UltraJSON uses the internal decoder, this double free is impossible to trigger from Python.

Patches

Has the problem been patched? What versions should users upgrade to?

Users should upgrade to UltraJSON 5.4.0.

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

There is no workaround.

For more information

If you have any questions or comments about this advisory:

Open an issue in UltraJSON

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`ujson`	all versions	5.4.0`pip install --upgrade 'ujson==5.4.0'`

Affected Products

2 products · 3 configurations

fedorafedoraproject

2 versions

3536

Application

ultrajsonultrajson_project

< 5.4.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ujson, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ujson to 5.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-31117 is resolved across your whole dependency graph.
Workarounds
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Product	Fixed in	Advisory
Red Hat OpenStack Platform 16.1	`python-ujson-0:2.0.3-3.el8ost`	RHSA-2022:8864
Red Hat OpenStack Platform 16.2	`python-ujson-0:2.0.3-3.el8ost`	RHSA-2022:8850

Frequently Asked Questions

### Impact _What kind of vulnerability is it? Who is impacted?_ When an error occurs while reallocating the buffer for string decoding, the buffer gets freed twice. Due to how UltraJSON uses the internal decoder, this double free is impossible to trigger from Python. ### Patches _Has the problem been patched? What versions should users upgrade to?_ Users should upgrade to UltraJSON 5.4.0. ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ There is no workaround. ### For more information If you have any questions or comments about this adv