CVE-2026-44660

Publication date 27 May 2026

Last updated 6 June 2026

Ubuntu priority

Cvss 3 Severity Score

Description

UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Prior to 5.12.1, when ujson.dump() writes to a file-like object and the write operation raises an exception, the serialized JSON string object is not decremented, leaking memory. Each failed write operation leaks the full size of the serialized payload. This vulnerability is fixed in 5.12.1.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
ujson	26.04 LTS resolute	Needs evaluation
	25.10 questing	Needs evaluation
	24.04 LTS noble	Needs evaluation
	22.04 LTS jammy	Needs evaluation
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
pandas	26.04 LTS resolute	Needs evaluation
	25.10 questing	Needs evaluation
	24.04 LTS noble	Needs evaluation
	22.04 LTS jammy	Needs evaluation
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	14.04 LTS trusty	Needs evaluation
collada2gltf	26.04 LTS resolute	Not in release
	25.10 questing	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Needs evaluation
	18.04 LTS bionic	Needs evaluation

Notes

ccdm94

the embedded ujson code in pandas, eventhough containing similar content as the upstream ujson code, seems to have diverged from the ujson upstream project (they have fully forked ujson), since pandas upstream is maintaining their own ujson bug fixes and changes without re-syncing with the ujson upstream project. There is no indication the ujson fork, as used in pandas, is vulnerable to the same issues as the upstream ujson code.

Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H