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CVE-2022-31117

Double free of buffer during string decoding in ujson

MEDIUM
5.9
CVSS Score
Published: July 5, 2022 at 05:30 PM UTC
Updated: June 17, 2026 at 04:44 AM UTC
3 products affected across 3 vendorsFedoraUltrajsonUltrajson

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Severity
MEDIUM5.9
Exploit prediction
EPSS 2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Fedora· Fedora Projectrpm
95%
3536
Ultrajson· Ultrajson Projectpypi
95%
v < 5.4.0
Affected range stops below 5.4.0, so it looks safe — our inference, not a vendor statement
Ultrajson· Ultrajson
60%
v < 5.4.0
Affected range stops below 5.4.0, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_MISCPatchThird Party Advisory
Source: [email protected]
https://github.com/ultrajson/ultrajson/commit/9c20de0f77b391093967e25d01fb48671104b15b
x_refsource_CONFIRMThird Party Advisory
Source: [email protected]
https://github.com/ultrajson/ultrajson/security/advisories/GHSA-fm67-cv37-96ff
Vendor Advisoryx_refsource_FEDORA
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NAU5N4A7EUK2AMUCOLYDD5ARXAJYZBD2/
Vendor Advisoryx_refsource_FEDORA
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OPPU5FZP3LCTXYORFH7NHUMYA5X66IA7/

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-415

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