CVE-2022-31117: medium-severity vulnerability in ultrajson
Double free of buffer during string decoding in ujson
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.9epss 1.9%
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
ultrajson · ultrajsonRelated CVEs — ultrajson
In the same product, most dangerous first.
CVE-2022-31116HIGHIncorrect handling of invalid surrogate pair characters in ujsonEPSS 2.5%CVE-2026-32874HIGHUltraJSON has a Memory Leak parsing large integers allows DoSEPSS 0.5%CVE-2026-32875HIGHUltraJSON has an integer overflow handling large indent leads to buffer overflow or infinite loopEPSS 0.5%CVE-2026-44660HIGHUltraJSON: Memory Leak in ujson.dump() on Write FailureEPSS 0.4%CVE-2026-54911MEDIUMUltraJSON: Malformed/Truncated UTF-8 Accepted and Silently Rewritten in ujson.dumps()EPSS 0.4%
References
https://github.com/ultrajson/ultrajson/commit/9c20de0f77b391093967e25d01fb48671104b15bhttps://github.com/ultrajson/ultrajson/security/advisories/GHSA-fm67-cv37-96ffhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NAU5N4A7EUK2AMUCOLYDD5ARXAJYZBD2/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OPPU5FZP3LCTXYORFH7NHUMYA5X66IA7/