CVE-2026-32874
Publication date 20 March 2026
Last updated 28 April 2026
Ubuntu priority
Description
UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Versions 5.4.0 through 5.11.0 contain an accumulating memory leak in JSON parsing large (outside of the range [-2^63, 2^64 - 1]) integers. The leaked memory is a copy of the string form of the integer plus an additional NULL byte. The leak occurs irrespective of whether the integer parses successfully or is rejected due to having more than sys.get_int_max_str_digits() digits, meaning that any sized leak per malicious JSON can be achieved provided that there is no limit on the overall size of the payload. Any service that calls ujson.load()/ujson.loads()/ujson.decode() on untrusted inputs is affected and vulnerable to denial of service attacks. This issue has been fixed in version 5.12.0.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| 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 |
Not affected
|
|
| 18.04 LTS bionic |
Not affected
|
|
| 16.04 LTS xenial |
Not affected
|
|
| pandas | 26.04 LTS resolute |
Not affected
|
| 25.10 questing |
Not affected
|
|
| 24.04 LTS noble |
Not affected
|
|
| 22.04 LTS jammy |
Not affected
|
|
| 20.04 LTS focal |
Not affected
|
|
| 18.04 LTS bionic |
Not affected
|
|
| 16.04 LTS xenial |
Not affected
|
|
| 14.04 LTS trusty |
Not affected
|
|
| ujson | 26.04 LTS resolute |
Fixed 5.11.0-3ubuntu0.1
|
| 25.10 questing |
Fixed 5.10.0-1ubuntu0.1
|
|
| 24.04 LTS noble |
Fixed 5.9.0-1ubuntu0.1~esm1
|
|
| 22.04 LTS jammy |
Not affected
|
|
| 20.04 LTS focal |
Not affected
|
|
| 18.04 LTS bionic |
Not affected
|
|
| 16.04 LTS xenial |
Not affected
|
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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 |
References
Related Ubuntu Security Notices (USN)
- USN-8219-1
- UltraJSON vulnerabilities
- 28 April 2026