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PatchSiren cyber security CVE debrief

CVE-2026-16554 DaveGamble CVE debrief

The cJSON library has an integer overflow vulnerability in the print_string_ptr() function on 32-bit platforms. This occurs when processing strings with approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service. The vulnerability has been confirmed in version 1.7.19 but may also affect other versions.

Vendor
DaveGamble
Product
cJSON
CVSS
MEDIUM 5.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-27
Original CVE updated
2026-07-27
Advisory published
2026-07-27
Advisory updated
2026-07-27

Who should care

Developers and users of applications that utilize the cJSON library on 32-bit platforms should be aware of this vulnerability. This includes those who use cJSON for JSON parsing and generation in their software.

Technical summary

The vulnerability is caused by an integer overflow in the print_string_ptr() function in cJSON.c. This function is used to print JSON strings, and the overflow occurs when processing strings with a large number of control characters. The vulnerability can be exploited by an attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform, potentially leading to remote code execution, information disclosure, or denial of service.

Defensive priority

Medium

Recommended defensive actions

  • Review and update cJSON library to a version that includes a fix for this vulnerability, if available.
  • Use cJSON on 64-bit platforms if possible, as the vulnerability only affects 32-bit platforms.
  • Implement input validation and sanitization for JSON strings to prevent exploitation.
  • Monitor for and apply patches or updates from the cJSON project or affected vendors.
  • Review compensating controls for exposed systems while remediation is scheduled and verified.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The vulnerability has been confirmed in version 1.7.19 of the cJSON library, but may also affect other versions. The project creator could not be contacted for further information. Evidence is limited to public CVE and NVD details. Defenders should verify cJSON library usage in their environments and review for exposure.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-27T09:16:37.383Z and has not been modified since then.