jackson-databind: PolymorphicTypeValidator bypass via generic type parameters allows arbitrary class instantiation
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 2.18.8, 2.21.4, 3.1.4
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- 2 proofs of concept on GitHub
- Exploitation: poc
- Automatable: no
- Technical impact: total
Summary
jackson-databind contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor. From 2.10.0 until 2.18.8, 2.21.4, and 3.1.4, jackson-databind's PolymorphicTypeValidator (PTV) is the primary safety mechanism guarding polymorphic deserialization. When polymorphic typing is enabled and a type identifier contains generic parameters (i.e. the type ID string contains <), DatabindContext._resolveAndValidateGeneric() validates only the raw container class name (the substring before <) against the configured PTV. If the container type is approved, the method parses the full canonical type string via TypeFactory.constructFromCanonical() and returns the fully parameterized type without ever validating the nested type arguments against the PTV. The nested type arguments are then resolved, instantiated, and populated as beans during deserialization. An attacker who controls the type ID can therefore place a denied class as a generic type parameter of an allowed container — for example java.util.ArrayList<com.evil.Gadget> when only java.util.ArrayList is allow-listed. The container passes the PTV check; com.evil.Gadget is loaded via Class.forName(name, true, loader), instantiated, and its properties are set from attacker-controlled JSON. This completely bypasses an explicitly configured PTV allow-list. This vulnerability is fixed in 2.18.8, 2.21.4, and 3.1.4.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- FasterXML jackson-databind
From 2.10.0 · fixed in 2.18.8; From 2.19.0 · fixed in 2.21.4; From 3.0.0 · fixed in 3.1.4
- com.fasterxml.jackson.core:jackson-databindMaven
From 2.10.0 · fixed in 2.18.8
- com.fasterxml.jackson.core:jackson-databindMaven
From 3.0.0 · fixed in 3.1.4
- com.fasterxml.jackson.core:jackson-databindMaven
From 2.19.0 · fixed in 2.21.4
- tools.jackson.core:jackson-databindMaven
From 3.0.0 · fixed in 3.1.4