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fkie_cve-2026-59990

Jawn is an open source JSON parser. Prior to 1.7.0, Jawn parse methods accept arbitrarily deep JSON array and object nesting without a depth limit, allowing a remote attacker who can submit untrusted JSON to grow parser contexts until the JVM heap is exhausted. The resulting java.lang.OutOfMemoryError is a fatal Scala error that is not ordinarily handled by scala.util.Try or cats.effect.IO, causing denial of service. This issue is fixed in version 1.7.0.

GHSA-cc4v-rvgp-2pf3 — Jawn: Uncontrolled nesting depth in JSON parser

Affected: Maven: org.typelevel:jawn-parser_2.12, Maven: org.typelevel:jawn-parser_2.13, Maven: org.typelevel:jawn-parser_3

The Jawn parser before 1.6.1 is vulnerable to a denial of service attack via untrusted input.

### Impact

A remote attacker who can submit JSON to any jawn-backed parse method can exhaust JVM heap and trigger `java.lang.OutOfMemoryError`. This is treated by Scala as a fatal error and not typically handled by `scala.util.Try` or `cats.effect.IO`.

### Patches

Version `1.6.1` introduces a configurable nesting-depth limit (`Parser#maxDepth`, default `4096`). Inputs deeper than the limit fail with a recoverable `ParseException` instead of exhausting heap.

Users who require deeper nesting may override `maxDepth` on a `Parser` subclass.

### Workarounds

- Enforce an input size limit small enough that the resulting context stack cannot exhaust heap, (e.g. http4s `EntityLimiter`). - Pre-scan untrusted input and reject documents whose maximum delimiter nesting exceeds a threshold before handing them to jawn.

UBUNTU-CVE-2026-59990

Affected: Ubuntu:20.04:LTS: jawn, Ubuntu:22.04:LTS: jawn, Ubuntu:24.04:LTS: jawn, Ubuntu:26.04:LTS: jawn