CVE-2022-31117: UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. In versions prior to 5.4.0 an error occurring while real...

Description

UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. In versions prior to 5.4.0 an error occurring while reallocating a buffer for string decoding can cause the buffer to get freed twice. Due to how UltraJSON uses the internal decoder, this double free is impossible to trigger from Python. This issue has been resolved in version 5.4.0 and all users should upgrade to UltraJSON 5.4.0. There are no known workarounds for this issue.

Metrics

CVSS 3.1

5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

1.39%

68.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-415

Affected Software

Vendor	Product	Versions
Ultrajson Project	Ultrajson	< 5.4.0
Fedoraproject	Fedora	35
Fedoraproject	Fedora	36

References

Timeline

Published: Jul 5, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-31117?

UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. In versions prior to 5.4.0 an error occurring while reallocating a buffer for string decoding can cause the buffer to get freed twice. Due to how UltraJSON uses the internal decoder, this double free is impossible to trigger from Python. This issue has been resolved in version 5.4.0 and all users should upgrade to UltraJSON 5.4.0. There are no known workarounds for this issue.

How severe is CVE-2022-31117?

CVE-2022-31117 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 1.39% probability of exploitation in the next 30 days.

How do I fix CVE-2022-31117?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.