USN-7973-1: cJSON vulnerabilities

USN-7973-1: cJSON vulnerabilities

Publication date: 23 January 2026
Overview: Several security issues were fixed in cJSON.

Packages
cjson - Ultralightweight JSON parser in ANSI C

Details
It was discovered that cJSON incorrectly handled parsing large numbers. An
attacker could possibly use this issue to cause a denial of service.
(CVE-2023-26819)

It was discovered that cJSON may perform out-of-bounds read when processing
specially crafted JSON files using parse_object. An attacker could possibly
use this issue to expose sensitive information or crash the program.
(CVE-2023-53154)

It was discovered that cJSON incorrectly validated array indices in JSON
pointers, which could result in an out-of-bounds memory access. An attacker
could possibly use this issue to cause a denial of service, or execute
arbitrary code. (CVE-2025-57052)

Update instructions
The problem can be corrected by updating your system to the following package versions:

• 25.10 questing libcjson1 – 1.7.18-3.1ubuntu0.1
• 24.04 LTS noble libcjson1 – 1.7.17-1ubuntu0.1~esm3
• 22.04 LTS jammy libcjson1 – 1.7.15-1ubuntu0.1
• 20.04 LTS focal libcjson1 – 1.7.10-1.1ubuntu0.1~esm1