Description
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.
References6
- github.com/typelevel/jawn/commit/191cb3a44e77f1afab439ee636bf66…
- github.com/typelevel/jawn/commit/6219666641f9408498f85868f835e1…
- github.com/typelevel/jawn/commit/93ac93e9c992c11b4c03d5455d8551…
- github.com/typelevel/jawn/commit/f6ace7e0db715de1a8c4618bed9378…
- github.com/typelevel/jawn/releases/tag/v1.7.0
- github.com/typelevel/jawn/security/advisories/GHSA-cc4v-rvgp-2p…
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 50 · as of 9 November 2026
- CWE
- CWE-770
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.