Resource exhaustion in jackson-core - CVE-2026-18401
Published: February 27, 2026
Vulnerability identifier: #VU123309
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-18401
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to the non-blocking (async) JSON parser in jackson-core bypasses the maxNumberLength constraint (default: 1000 characters) defined in StreamReadConstraints. A remote attacker can send JSON with arbitrarily long numbers through the async parser API and exhaust CPU resources, leading to a denial of service condition.
Affected software
jackson-core
How to mitigate CVE-2026-18401
Install updates from vendor's website.
jackson-core - addressed in versions 2.18.6, 2.21.1