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.

The remote Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8219-1 advisory.

    Cameron Criswell discovered that UltraJSON contained a memory leak that would occur when parsing large     integers. An attacker could possibly use this issue to cause UltraJSON to crash, resulting in a denial of     service. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-32874)

    It was discovered that UltraJSON contained integer overflow/underflow issues when calculating how much     memory to reserve for indentation in certain instances. An attacker could possibly use this issue to cause     UltraJSON to crash, resulting in a denial of service. (CVE-2026-32875)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

An update of the python3 package has been released.

The remote Fedora 42 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-0f099ed388 advisory.

    Update to 5.12.0. This release updates the license field in the Python     metadata and fixes a buffer overflow/infinite loop from indent handling.


Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-bf741e26e4 advisory.

    Update to 5.12.0. This release updates the license field in the Python     metadata and fixes a buffer overflow/infinite loop from indent handling.


Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2026-32874)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
310932	Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : UltraJSON vulnerabilities (USN-8219-1)	Nessus	Ubuntu Local Security Checks	high
307435	Photon OS 5.0: Python3 PHSA-2026-5.0-0827	Nessus	PhotonOS Local Security Checks	high
307419	Photon OS 4.0: Python3 PHSA-2026-4.0-1000	Nessus	PhotonOS Local Security Checks	critical
303288	Fedora 42 : python-ujson (2026-0f099ed388)	Nessus	Fedora Local Security Checks	high
303283	Fedora 43 : python-ujson (2026-bf741e26e4)	Nessus	Fedora Local Security Checks	high
303239	Linux Distros Unpatched Vulnerability : CVE-2026-32874	Nessus	Misc.	high

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CVE-2026-32874

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