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[ CVE-2026-89425 · Published 23 Sep 2026 ]

jackson-core: UTF8DataInputJsonParser._reportInvalidToken() missing maxErrorTokenLength limit -> unbounded StringBuilder growth (DoS)

CVSS 7.5 EPSS <1%2 agency advisoriesFix available

[ Why it matters ]Priority signals

  • Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

UTF8DataInputJsonParser._reportInvalidToken() in FasterXML jackson-core builds the offending-token text for its error message by appending Java identifier characters to a StringBuilder in a loop that has no upper bound. Unlike the three sibling parser implementations, including UTF8StreamJsonParser, it never consults ErrorReportConfiguration.getMaxErrorTokenLength() (default 256). A malformed token supplied to a parser created through JsonFactory.createParser(DataInput) is therefore accumulated in full. No StreamReadConstraints setting mitigates this: maxDocumentLength cannot be applied to DataInput sources at all, and maxStringLength does not cover this path because the accumulation bypasses ReadConstrainedTextBuffer. The reporter measured a 20,000,109-character exception message from a 20-million-character malformed token on the DataInput path, against 367 characters for identical input on the InputStream path. Scaling the payload drives the StringBuilder, which also incurs byte-to-char expansion and internal array doubling, to many times the raw payload size and can trigger OutOfMemoryError for the whole JVM. UTF8DataInputJsonParser was introduced in 2.8.0 together with createParser(DataInput); releases before 2.8.0 do not contain the affected class.

[ Fixes ]Fixes and patches

[ Advisories ]Government CERT advisories

[ Packages ]Affected open-source packages

  • com.fasterxml.jackson.core:jackson-core mavenAffected >= 2.19.0, <= 2.21.6 · fixed in 2.21.7 · GHSA-7hhh-6rmp-j9qf
  • com.fasterxml.jackson.core:jackson-core mavenAffected >= 2.22.0, <= 2.22.2 · fixed in 2.22.3 · GHSA-7hhh-6rmp-j9qf
  • tools.jackson.core:jackson-core mavenAffected >= 3.0.0, <= 3.1.6 · fixed in 3.1.7 · GHSA-7hhh-6rmp-j9qf
  • tools.jackson.core:jackson-core mavenAffected >= 3.2.0, <= 3.2.2 · fixed in 3.2.3 · GHSA-7hhh-6rmp-j9qf
  • com.fasterxml.jackson.core:jackson-core mavenAffected >= 2.8.0, <= 2.18.10 · fixed in 2.18.11 · GHSA-7hhh-6rmp-j9qf

[ References ]References