Amazon Linux 2023 Security Advisory: ALAS2023-2026-3208
Advisory Released Date: 2026-10-12
Advisory Updated Date: 2026-10-12
jackson-databind's deserializer for java.nio.file.Path resolves an attacker-supplied URI without restricting the URI scheme. In JDKFromStringDeserializer.NioPathHelper.deserialize, a string bound from untrusted JSON is passed to new URI(value) and then to Path.of(uri). When that throws FileSystemNotFoundException, the code enumerates ServiceLoader<FileSystemProvider> and calls provider.getPath(uri) on the first provider whose scheme matches the attacker-chosen scheme. Untrusted JSON can therefore select and drive an arbitrary registered FileSystemProvider during readValue under a default JsonMapper, and forces provider class loading at the same time. With only the JDK built-in providers (file, jar/zipfs) present, the resolved path is inert and no mount or network I/O occurs; further impact requires a side-effecting third-party FileSystemProvider on the classpath. This affects com.fasterxml.jackson.core:jackson-databind from 2.8.0 before 2.18.10, from 2.19.0 before 2.21.6, and from 2.22.0 before 2.22.2, and tools.jackson.core:jackson-databind from 3.0.0 before 3.1.6 and from 3.2.0 before 3.2.2. Users should upgrade to 2.18.10, 2.21.6, 2.22.2, 3.1.6, or 3.2.2. Binding java.nio.file.Path from untrusted JSON should be avoided regardless of version. (CVE-2026-19032)
DefaultBaseTypeLimitingValidator is the PolymorphicTypeValidator applied automatically whenever @JsonTypeInfo is used without an explicitly configured custom validator. It denies polymorphic resolution only for a fixed set of "unsafe base types", and its isSafeSubType method returns true unconditionally for every base type outside that set. java.lang.Comparable was absent from the list despite being implemented by a very large fraction of JDK and application classes, comparable in breadth to java.io.Serializable, which is on the list for that reason. An application declaring an @JsonTypeInfo-annotated property or class with Comparable as its base type, and no custom PolymorphicTypeValidator, will accept a type identifier for essentially any class implementing Comparable. This yields an attacker-controlled object instantiation primitive; a demonstrated case constructs a java.io.File for an arbitrary attacker-chosen path, which becomes path-traversal-adjacent if the application subsequently calls path-sensitive methods on the value. No class implementing Comparable has been identified that yields code execution through deserialization alone. Global Default Typing via activateDefaultTyping is not affected, because that method structurally requires an explicit PolymorphicTypeValidator argument. This affects com.fasterxml.jackson.core:jackson-databind from 2.11.0 before 2.18.10, from 2.19.0 before 2.21.6, and from 2.22.0 before 2.22.2, and tools.jackson.core:jackson-databind from 3.0.0 before 3.1.6 and from 3.2.0 before 3.2.2. Users should upgrade to 2.18.10, 2.21.6, 2.22.2, 3.1.6, or 3.2.2. (CVE-2026-83557)
Affected Packages:
jackson-databind
Issue Correction:
Run dnf update jackson-databind --releasever 2023.12.20261012 or dnf update --advisory ALAS2023-2026-3208 --releasever 2023.12.20261012 to update your system.
More information on how to update your system can be found on this page: Amazon Linux 2023 documentation
noarch:
jackson-databind-2.21.7-1.amzn2023.0.1.noarch
src:
jackson-databind-2.21.7-1.amzn2023.0.1.src