CVE-2026-25790: Wazuh has Stack-Based Buffer Overflow in Security Configuration Assessment JSON Parser

Severity: high (CVSS 7.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-03-17 · updated 2026-06-17
Weakness: CWE-121

Description

Wazuh is a free and open source platform used for threat prevention, detection, and response. Starting in version 3.9.0 and prior to version 4.14.3, multiple stack-based buffer overflows exist in the Security Configuration Assessment (SCA) decoder (`wazuh-analysisd`). The use of `sprintf` with a floating-point (`%lf`) format specifier on a fixed-size 128-byte buffer allows a remote attacker to overflow the stack. A specially crafted JSON event can trigger this overflow, leading to a denial of service (crash) or potential RCE on the Wazuh manager. The vulnerability is located in `/src/analysisd/decoders/security_configuration_assessment.c`, within the `FillScanInfo` and `FillCheckEventInfo` functions. In multiple locations, a 128-byte buffer (`char value[OS_SIZE_128];`) is allocated on the stack to hold the string representation of a number from a JSON event. The code checks if the number is an integer or a double. If it's a double, it uses `sprintf(value, "%lf", ...)` to perform the conversion. This `sprintf` call is unbounded. If a floating-point number with a large exponent (e.g., `1.0e150`) is provided, `sprintf` will attempt to write its full string representation (a "1" followed by 150 zeros), which is larger than the 128-byte buffer, corrupting the stack. Version 4.14.3 patches the issue.

Affected products

wazuh: from 3.9.0 before 4.14.3 — fixed in 4.14.3

How to fix

Upgrade to a fixed version: wazuh 4.14.3. Check the vendor advisory for mitigations.

References

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