UBUNTU-CVE-2026-32874

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.getintmaxstrdigits() 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.

References

Affected packages

Ubuntu:Pro:24.04:LTS / ujson

Package

Name: ujson
Purl: pkg:deb/ubuntu/ujson?arch=source&distro=esm-apps%2Fnoble

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

5.9.0-1ubuntu0.1~esm1

Affected versions

5.*

5.8.0-1

5.8.0-1build1

5.9.0-1

5.9.0-1build1

Ecosystem specific

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_version": "5.9.0-1ubuntu0.1~esm1",
            "binary_name": "python3-ujson"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-32874.json"

Ubuntu:25.10 / ujson

Package

Name: ujson
Purl: pkg:deb/ubuntu/ujson?arch=source&distro=questing

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

5.10.0-1ubuntu0.1

Affected versions

5.*

5.10.0-1build2

Ecosystem specific

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_version": "5.10.0-1ubuntu0.1",
            "binary_name": "python3-ujson"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-32874.json"

Ubuntu:26.04:LTS / ujson

Package

Name: ujson
Purl: pkg:deb/ubuntu/ujson?arch=source&distro=resolute

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

5.11.0-3ubuntu0.1

Affected versions

5.*

5.10.0-1build2

5.10.0-1build3

5.11.0-3

5.11.0-3build1

Ecosystem specific

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_version": "5.11.0-3ubuntu0.1",
            "binary_name": "python3-ujson"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-32874.json"