CVE-2026-110879: jackson-databind type validation bypass in generic arguments

CVE-2026-110879 · Severity: critical · CVSS 9.8 · Published 2026-10-28

jackson-databind is a Java library used to parse and generate JSON data. An attacker can bypass type validation for generic arguments in class-name polymorphism, allowing deserialization of arbitrary classes. When combined with certain configurations and libraries like Spring, this enables remote code execution through instantiation of gadget classes with attacker-controlled properties.

Technologies: FasterXML Jackson Databind. Vendors: FasterXML.

Quick answers

Is CVE-2026-110879 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-110879 being exploited in the wild.
How severe is CVE-2026-110879?
Critical severity, with a CVSS score of 9.8, published 28 October 2026.
Which products and versions are affected?
FasterXML Jackson Databind 2.10.0 through 2.x (before fix), 3.0.0 through 3.x (before fix); Tools.Jackson.Core Jackson-Databind 3.0.0 and later (before fix).
Is there a fix for CVE-2026-110879?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-110879 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-110879?
Check whether you run FasterXML Jackson Databind or Tools.Jackson.Core Jackson-Databind at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability exists in DatabindContext._resolveAndValidateGeneric(), which validates the outer class against the declared base type but fails to properly validate generic arguments against their corresponding declared bindings. The validator is passed arguments that have not undergone subtype checks, and when LaissezFaireSubTypeValidator is substituted (via allowIfBaseType rules), embedded arguments escape all restrictions. Array element types are similarly left unvalidated after base-type approval, enabling gadget instantiation with attacker-supplied properties.

Affected products

  • FasterXML jackson-databind 2.10.0 through 2.x (before fix), 3.0.0 through 3.x (before fix)
  • tools.jackson.core jackson-databind 3.0.0 and later (before fix)

Timeline

  • 2026-10-28: disclosed

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